How to install artificial grass on concrete

Concrete entrance

Before artificial grass installed on concrete driveway

Artificial grass is an extremely versatile product and can be laid pretty much anywhere if done correctly.

Laying artificial grass on concrete can be a great option for you because:

  • It is kid friendly and will soften any falls
  • It will break up a bland concrete area with some colour
  • It will last longer than concrete
  • It is as cheap if not cheaper than concrete
  • It is quick to lay artificial grass
  • It will last 10 years plus if installed correctly
  • It can be used to completely cover the concrete or just sections of it

I have previously written a general guide on installing artificial grass on soil. This guide will take you through 6 simple steps on how to install artificial grass on concrete. If the concrete is in good condition and drains well it is cheaper and easier than installing artificial grass on soil as the concrete will act as the solid base on which to fit the grass doing away with the need for the groundworks.

These are the steps we take for installing fake grass on concrete:

1. Prepare the equipment needed 

Tools we use for the work

2. Measure and order your artificial grass

If you intend to lay the artificial grass on the concrete surface yourself you will firstly need to assess how much grass you will require. We have written a useful article on how to measure your space so that you order the correct amount. Then choose the artificial grass that is best for your requirements and call us on 020 81664168 to order the grass and arrange a delivery date. You will generally want a shorter pile grass if you anticipate the area will have a lot of footfall.

3. Check your existing drainage

Does the concrete you intend to lay the artificial grass on drain well? Ideally it should have a slight fall. If it does great – no further action is required. If it doesn’t drain well use a Hammer Drill with a 16mm Bit in the poorly draining areas and then fill these holes with pea gravel.

4. Is the area you intend to lay artificial grass smooth?

If the concrete surface is relatively smooth you can lay directly on it after brushing it clean and removing any debris. I would recommend an artificial grass product with a deep pile to give the grass some bounce and to prevent any of the contours in the concrete being visible. A compromise will be needed though if you expect a lot of people walking over the grass as in this case a shorter pile is more preferable.

If your surface is unsmooth an underlay will be required as any imperfections in the concrete surface will show through to the top surface. We use a 10mm Foam Shockpad Underlay. The underlay can be spread out in any direction over the concrete area to be covered. We just use a little gaffer tape to hold it in place. The grass will hold it more securely once that goes on. The underlay we recommend allows water to drain through.

5. Laying the artificial grass on the concrete

Simply lay the artificial grass on to the smooth, flat area to be covered. Cut to shape with a sharp Stanley Knife using Hook Blades and leave for a few hours to settle. Stick the grass lightly around the perimeter with Astro Pro Seaming Adhesive. Remember too much glue will stop water escaping and you will never be able to lift and replace the grass if needed. So look where the water is likely to run off and make sure to leave gaps between the glue for it to escape. Glue as close to the edge of the perimeter as you can.

We always use Artificial Grass Joining Tape if making a join rather than sticking the join directly to the concrete, as we want as little glue down as possible. Here are some more detailed instructions on joining the grass.

6. Add kiln sand to the fake grass

When the artificial grass is fully dry add a layer of Kiln Sand paying particular attention to the areas close to doors or gates. The sand will help pin the grass to the ground in these well trodden areas.

Take a look at a project where we installed artificial grass on concrete

Following these steps you too will be left with an artificial grass flooring that will brighten up your space. Good luck if you intend laying the artificial grass yourself. If you would like us to provide you with a quote for supplying and installing the grass please either fill out this form or give me a call on 020 81664168.

104 Comments

  1. Hi there, fab info, could just do with a bit of advice tho!
    I currently have ‘textured’ flag stones down and am looking at my best options of laying artificial grass on top. I dont want to cut corners, but dont want to make work for myself either! Drainage, i’m sceptical about, it does seem to collect in certain areas which I probably hadnt noticed before, but it does disappear! For this i’m considering drilling holes and filling with the pea shingle I have read about! The slabs are textured, so not perfectly smooth! After ‘researching’, i had looked at doing a timber frame to house a 75 mm sub base made from 10 mm compacted limestone chipping (in case of potential drainage issues), presumably this would be laid level and not on a fall due to the potential drainage problem, and then following that add, again level, 25 mm laying course of compacted limestone dust before screeding and laying the grass. As the slabs are only textured and not raised, i dont know if the slabs could be used as the solid sub base and add the limestone dust to create the smooth surface on top of the slabs and under the grass! I did see info on a previous question about 10 mm foam shockpad underlay over a non even concrete surface as this serves as drainage too, but if this is more expensive than doing a limestone subbase i would rather do the subbase!! Lastly! Is it ok to drill into the finished product?! I have a small fence i want to put up, of which i require 2 square metal support plates to be screwed down for the fence posts! Many thanks in advance for your help. I have also attached a picture (hopefully) of where the water has been holding to see your opinions on if this is a drainage issue or not!

    • Hi there , personally there are 3 avenues to potentially go down. Firstly, the use of a thin shock padding after drilling 15mm cores in badly drained areas and filling we pea shingle . Secondly, concreting in fixing timbers around the perimeter and leaving a 20 mm lip , improving the drainage by either drilling cores or smashing some of the flags to improve drainage in the bad areas, before filling in with granite dust and prepping a nice firm/smooth surface . Thirdly removing the flags and using the mortar base underneath as your sub base ie do as above but filling in any areas with type one and smashing through the mortar to improve the drainage.
      All these methods have been used successfully and there is no right or wrong way its purely down to budget and work load. regards

      • Thanks for replying and for the information!
        So, if I drilled holes for drainage and filled with pea shingle, and water didn’t hold, then the slab base could serve as the sub-base, and going forward, put a frame down (i’m a little confused about the 20mm lip you referred to)?, weed membrane, and then 25 mm compacted limestone dust over to ensure an even surface for the grass to go on? At this point is the compacted dust solid enough to be able to drill into to secure my fence supports?
        I need to try and ensure any water is clearing first. Ideally I would rather put a sub base down over the slabs if drainage continued to be a problem rather than pulling the slabs up. Budget wise that would be more cost effective than skip etc etc to take the slabs up.
        If drainage continued to be a problem after drilling holes, by laying a sub base would this be done level or with a slight fall to help with drainage, or does the sub base manage this itself?! I don’t want to cut corners and have issues with the grass, but what started off as a reasonably priced lockdown job is turning into a project having done a bit of research!! Thanks for your help!

        • Hi there post wise, they would all need to be fitted and secured first before any work on grass starts. The 20 mm lip around the edge using concreted in timbers allows you to build up with granite dust to the top of these levels and makes the area self contained otherwise it would get washed away over time. Personally there is no point using type one on top of the slabs as they are your sub base, I would only use this type one if you do lift …the idea of lifting the slabs and breaking up the mortar base allows for the water to escape quicker. The issue you have is, if the drainage holes get clogged and the area is self contained around the edges it then becomes waterlogged in times of bad weather. Regards

          • Hi Gavin
            Well further to my plans that you gave advice about a few months ago, i’m fairly impressed with myself having built a timber frame around my backyard area to accommodate the 25 mm laying course over the existing flagstones, to then fit the membrane and then the artificial grass. Being aware of the importance of drainage, I allowed it to rain to ensure the water cleared. It’s become evident an approximate 2 sq metre area isn’t level and so water is holding more in that area and taking longer to drain than the rest! My theory is to level it off using more limestone dust that I have used, however, if this is the case, can I add on top of the existing compacted area, and would new dust effectively ‘gel’ together with the existing, or would I need to pull some of the existing compacted dust back before putting new dust down and compacting? Any help, advice and information would be appreciated! Hopefully this will be the last hurdle before getting the grass down!!

          • Hi there , what process did you end up using ie did you take up the flags and use mortar as sub base/ add extra type one or did you break up flags and add granite? I assume you have gone on top of the flags , did you break them up? If not I would drag back the granno in the area where it dips and smash up the flags or even remove . Id make sure also that mortar base under them is permeable . Once this is done simply add whatever you need dust wise (its fine to add old and new , however it maybe a good idea to rake the old to break up the surface making it easier to bind) . Then once completed compacted screed to create your finished surface which should be at the same level as the top of the fixings . regards

  2. Hi Gavin, I have built a balcony ontop of a home extension. The roof is 18mm ply with a firestone EPDM rubber ontop. The balcony is 4m wide and drops 60mm from the back to the front as a gradient for water run off.
    CanI lay artificial grass directly on this or will the low gradient cause the grass to retain water? If so, can I use a drainage matt below the artificial grass perhaps to allow the water to run off? Many thanks in advance.

    • Hi as long as the water has somewhere to go when it runs off it will be absolutely fine You may need to consider fixing method onto the surface , ie ideally it would be stuck intermittently allowing water to escape from under the product. regards

  3. Hi
    I am wanting to fix artificial grass to an ugly 2.5 ft breeze block wall. Can I just glue it or will I have to nail/screw it?

  4. Hi Gavin,

    I’ will be laying 10mm underlay / shock pad under Artificial Grass on top of flag stones.
    Area is 6m x 8m, and the underlay comes in rolls 1.5m wide and so is to be taped together to fit (I believe).
    I also understand that I glue down the artificial grass around the perimeter only, but I can’t find if I glue the underlay at the perimeter only, or glue down the entire area, or something like glue perimeter but also glue a few stripes across the internal area?
    There is a slight decline on the area, I plan on rolling the grass down (2 x 4m width rolls), does it matter if also roll underlay down, or should it be rolled across, or does it really not matter?

    Any advice is much appreciated.

    Thanks
    Emmett

    • Hi I am not really a fan of underlay at all due to this reason, I personally would spend the money on a deeper/denser pile grass as these issues are avoided. It doesn’t really matter which way the underlay is rolled you just need to keep it in place for you to be able to lay the product. We generally tape it sporadically with gaffer tape, don’t forget water needs to escape if you are not using a pre holed underlay like x matting.

      You will not be able to glue the underlay as the glue will simply pull the underlay apart due to its strength. We generally leave a 1 inch gap around perimeter to glue the grass directly to surface, leaving gaps again for water to escape. We add weight by brushing in kiln sand into the grass pile which will reduce any puffing caused by the underlay.
      regards

      • Your comment is awaiting moderation.

        Appreciate the response!
        I’m installing 35mm grass, the 10mm underlay is only because i’m putting the grass down for our young kids / toddlers to play outside, Its not critical fall height thickness, but they’ll not be climbing such heights, so the 10mm is just a bit of extra padding.

        I’ve also considered adding kiln sand, but don’t like the idea of the clean up everytime the kids come in running in and out though, or would this not be an issue?

        The idea of gluing the grass direct to surface makes sense, is 1 inch enough of a glue perimeter?

        • Hi there, the kiln sand is simply brushed into the pile so it physically disappears, so that’s not an issue. One inch is enough, as you will get a slight ridge and you want that as close to the edge as possible. regards

      • Hi Gavin what would you recommend if we are putting fake grass down over existing laid solid concrete flags in an internal swimming pool surrounding?

        • Hi there , yes this is absolutely fine . I would ask a few questions when buying the grass making sure it is a good quality product .Prior to laying make sure the area is free draining , if not you may wish to drill 15 mm cores and fill with pea shingle. regards

  5. Hi Gavin
    I have just opened a dog Day care centre (6-10 dogs per day). I have managed to artificial grass the areas which were just mud and these are doing well as they are washed down with kennel dissinfectant and obviously drain well. I have a large bricked area though with a drain in the middle, one small area of the yard collects water as there is a little dip. Due to the ice and heat on the dogs paws I have been using Eva foam mats but these are not suitable in the wind. Would I be able to roll out and tape together artificial grass for a large area like this? Maybe using something to build up that water collecting area first? There are a few other uneven areas too.
    Thanks
    Abi

    • Hi there , grassing larger areas using tape and glue is fine as it acts like a floating surface . Avoid sticking the grass down using too much glue as it will stop the flow of water/urine escaping .
      As for the dip , you wont be able to use a fine aggregates as it will move and wash away very quickly. Try using a self levelling compound or cut out the area and re concrete. Always use a very short grass when using the areas for dogs. regards

  6. Hi Gavin, i have two areas of artificial grass to fit. One is around 5m x 4m and one is 5m x 5m. I have sunk in and fixed wood covered in plastic sheet around all areas for levels and left around 1″ to the top. I was going to uses sharp sand to level as a top, then fit membrane and then the grass, but after reading many of your mails on here that does not seem right?
    Alternatively i was going to mix some cement into it effectively creating a solid level concrete base then lay the grass on top, but i do have two dogs so worried about smells?
    Would you suggest using the granite instead or going with the sand and cement and drilling drain holes?
    Cheers
    Simon

    • Hi Im sorry to say this is recipe for disaster . What you have created is a sand filled bowl which will be full of dog wee. Firstly the idea of putting timber down and using aggregates on top is a huge no ,as the timber will warp and rot quickly as well as retaining the water , secondly if you then drill holes ,the sand will wash through and the grass will sink. My advise ,is to rip it up and start again from scratch using type 1 as the base to build on instead of timber. Don’t forget a permeable membrane must be used underneath the aggregates.regards

  7. Hi Gavin –

    We are buying a house that has an all-concrete yard so we’d like to add a dog run to the one side of the house.

    My plan now is to buy some kind of drainage mat and put that under the turf, then top with durafill. Will that be adequate drainage if the dogs are peeing on it (we would plan to hose it down occasionally and use odour-control spray).

    Also, how would we edge this if it’s on concrete and we can’t drill the edging into place? Could we put an edging strip in and use pea gravel or similar around the outside edge to weigh it down?

    Thanks!

    • Hi the problem will laying on concrete , it will trap the wee and even if you top with a wee odour product the smell will be coming from underneath as well. Im afraid you need to rethink and lift the concrete if there is no other place to put this.regards

  8. Hey Gavin,

    Great article.

    Hope you can help – I’d like to lay artificial grass on our tiled patio, the tiles are slightly textured, the patio has walls on all sides and the only drainage is in the centre of the patio and there a couple of places water does pool. I really don’t want to cause any drainage issues… any advice would be greatly appreciated.

    Thanks

    • Hi well there is nothing you can do if you do not wish to ruin the tiles. If you are not worried about the tiles you can drill cores in them and add pea shingle , or alternatively you can use self levelling compound to take the dips out. You can simply lay the grass over all of it including the drain and the water will pass through it , again if you do not wish to glue you could heavily sand the grass with kiln to pin it down.
      regards

  9. Hello Gavin

    I have a garden patio currently with patio slabs on it. None of the slabs are fixed by any cement or adhesive, and the slabs are in a square, kept in place by flower bed borders at the East & West perimeter. The design of the slabs means it’s not 100% flat, but pretty close. The existing drainage is great, the slabs sit on a mix of stone and condensed sand, and the water runs away lovely with no pooling.
    Over the last couple of weeks I have killed off the weeds that were appearing through the gaps between the slabs.

    As the drainage is so strong, and the surface is basically flat, I’ve thought about laying a weed membrane on top of the slabs, then rolling the grass straight on top of that. I thought sporadically gluing the grass to the concrete around the perimeters, making sure I don’t glue all the way around, as I know this will impact the drainage.
    Another thought I’d considered is flipping all the slabs so that the design is face down, with the flat surface now face up.

    In principal, do you think this will work? Just rolling over the existing slabs? Thank you!! 🙂

    • Hi well as long as there are no pot holes etc it should be fine , you may wish to fill any with some type 1 to create a rock hard surface that is free draining. I’m not a fan of adding fines on top as it will get washed away .
      regards

  10. Hello Gavin

    We have an area approx 4.5m x 5m. The area previously had slabs on it for a number of years. Under the slabs (and what is currently now there) is a lot of stone/pebbles covered by quite a thick layer of compacted sand.

    Because the sand is already quite flat as is, I was just going to treat the existing weeds, level the sand and lay the grass straight on top, pinning the grass at the perimeters with the sand?

    As the base is currently sand and stone, I think the drainage should be more than adequate as is, unless you think I still need to take action?

    My real question is, should I just lay the grass as is, or should I add some newer sand to the existing compacted sand, and should I use a weed membrane? Also, will pinning the perimeters work by pinning directly into the sand?

    Thank you

    • Hi there, sometimes it is simply about working with what you have. The drainage is good and the base isn’t moving anywhere, as its been down a while and pretty compacted. What I would suggest is to spray all weeds off with Round Up weedkiller. Around the edges I would make a 3inch by 3inch channel and put in a concrete fillet (mix of cement, ballast and water), simply smooth it off so its completely level with the top of your base. I would only add some more sharp sand to make sure its perfectly level, don’t add too much sharp sand as it tends to move and it sounds as though your base is pretty compact. Once happy your base is as flat as you can get it simply roll out grass, cut in, join etc and then stick it around the perimeter on your dried out fillet. This will stop any issues occurring around the perimeter as time goes by. If you wish to add a membrane before you lay the grass this can simply be added, however it is more hassle than it is worth on top as it causes issues with the grass when fitting.
      regards

  11. HI Gavin

    We are looking to lay artificial grass on a flat concrete square (essentially, 4.86m x 4.48m) with concrete border edging on the left and the right where the flower beds are, concrete wall at the top and nothing at the bottom, as it is a step down. Previously there were 1ft square slabs that have since been taken up, and the area has been cleared of debris, and weed killer has been applied. I intend to drill (approx) 12x 16mm holes and fill with 10mm shingle just to be safe with the drainage.

    I then intend to roll out the grass, join it using tape where needed, and lightly glue the perimeters to assist with drainage.

    Is there anything I am missing?

    Thanks in advance, great site, and great you’re helping so many people

    • Hi there, spot on mate, as long as the surface is pretty flat the grass will be absolutely fine. You may wish to brush in some kiln sand ,maybe 2 x 25 kg bags to pin it down and improve durability if it will get lots of footfall , this will also take the edge of any sharpness in the under surface.
      regards

      • Fantastic, will definitely do that with the kiln sand.

        Thank you so much for the prompt response, and keep up the great work mate!

        Best wishes for the future

        Jimmy

  12. Hi Gavin
    We are using a foam underlay on top of our patio slabs. I realise what you say regarding leaving a 1/2 inch gap around edging when placing the foam and thanks for the tip regarding gaffer tape!!! but what about the artificial lawn itself should we leave a gap also when this sits on top or should it go up tight against wall/sides?
    Many thanks Dez

      • Hi Gavin
        Used self levelling compound to help the patio slabs but wasn’t great and some puddles were left after we did hosepipe test! So to help drainage I drilled 16mm holes all over the patio area paying attention to problem areas (mostly puddles!) and my question is shall I fill in holes with 10mm shingles to the top?
        Many thanks Dez

  13. Hi,
    I am renting a property and the outdoor area is all bricks, but we would love to have grass for our toddler to play on. Can the artificial grass be laid without causing any damage or marking to the ground underneath? So that when we move out and remove the grass the ground will still be in the same condition. We had though of just placing the grass and not using any glues or adhesive but I’m worried it will move around or be a hazard. We could but some planters on the edge if that would hold it. Also will we need sand/cushioned underlay for it to be soft to play on at a 30mm thickness? Any help would really be appreciated, thanks

    • Hi there , on bricks as long as they are pretty flat and free draining if you wish to add grass as a temporary solutions and you do not wish to spoil whats underneath you can simply roll out the product.
      I would cut to size and then to add weight I would brush in a few bags (maybe more depending on size) of kiln dried sand as this will hold it down. The planters will also hold it in place . The only issues will be areas where you step on and off and these could become trip hazards .
      regards

  14. Hi I am planning on laying artificial grass directly onto my existing slabbed patio. I’ve just read you say no need to lay underlay just thicker grass so can you advise which is a more suitable height 26mm or 30mm? Also any guidance to laying would be really appreciated. Many thanks

    • Hi there a thicker grass hides more lumps and bumps however 4mm doesn’t make huge amounts of difference. Make sure the area is clean, if there are any pooling areas when it rains you may wish to drill some 15mm cores and fill with pea shingle. When ready fit grass, do not over stick, leave areas for water to escape around perimeter. regards

  15. Hi, I’ve got a concrete base under current paving flags which I’m getting rid of. The concrete base is around 250mm thick so not really viable to dig out. The concrete isn’t in the best of condition judging by the appearance when I’ve lifted a few flags. What would be the best way to lay down the grass? Would a timber sub frame to bring the garden up and self levelling compound be ideal or another way you’d recommend?

    Thanks!

    • Hi there, what we have done before is to use the patio base as the sub base. If you can concrete in some 3 x 2 timbers around the perimeter and set these leaving a 1 inch lip over the sub base you can then in fill using compacted granite dust 0-5 mm. If there are any areas which are lower and need building up simply fill with Type 1.
      regards

  16. Great site. I have an integral garage which is 20′ wide and protrudes from the house by over 9′ creating a 20′ x 9′ roof terrace. The protruding area has a beam and block roof covered with a concrete slab, which has a fall over the full 20′ width. At the end of the fall is the 9′ open end fitted with iron railings. The 20′ length has a house wall one side and a low balcony wall on the other side.
    My question is, this site is coastal and subject to very severe winds, how can I ensure efficient rainfall run off from under the turf and at the same time, prevent the severe winds from ripping up the turf.
    I have considered laying a central strip of turf over the 20′ with timber runners each side, however, this still leaves the end vulnerable.

    • Hi there I would stick it directly down onto the slabs/blocks around the perimeter leaving gaps of a foot every foot or so and obviously stick round the corners and access points . This will allow water to pass through under the grass as it moves down the incline to the drainage points. You can also use kiln dried sand on top, brushed in, to add weight if required.
      regards

  17. Hello, we are installing turf in the lower level of our backyard. There is a retaining wall that runs along the back, and it has a footer that runs about a foot out from the bottom of the wall. What would be the best way to secure the turf next to the wall since I can’t drive stakes in? I can’t raise the elevation of the dirt enough to make it see enough for stakes because it would cause drainage issues around our home. Thank you for your time!

    • Hi there , we always concrete our fixings in so there is less chance of movement . You may be able to concrete in a 3 by 2 or turn it on its side. If not simply put in a concrete fillet using sharp sand so you can stick the grass to it when its cut in.
      regards

  18. Hi Gavin

    I have a concrete slab 4.5m x 3.5m good condition and level
    I want to lay artificial grass on this then put a hot tub on there, it has had a hot tub on the slab before.
    Do I just tack the edges of the grass so it will allow any water to drain.
    I will be putting a good quality gazebo around the tub size is 4 x 3
    Do I put kiln sand on the grass

  19. Hi Gavin,
    We have 22 cast concrete steps leading down from our garden into our house as our house is set into a hill. Can the steps be covered in artificial grass much the same as straits are covered in carpet? It’s a long fall down these steps if you were to trip or slip on them and I’m thinking the grass would be a good non slip surface and also cushion an fall to some extent. I’ve not seen it used on steps so wondering if it is possible. Many thanks.

    • Hi there my advise would be to consider another surface. Yes the grass can be laid down steps but you would have to glue it so heavily, so there is no trip hazard that if you ever wish to remove it it will be impossible.
      Initially the grass will offer some extra cushion however the grass will get squashed very quickly with constant footfall and it also will be slippery in the winter when it becomes icey.
      regards

  20. Hi i am wanting to put artificial grass on a concrete surface which is bumpy in a few places how can i smooth them out i dont want the artificial grass to get damaged from constant rubbing will abit of dand do the trick also do u have to build a frame to stop the sand escaping

    • Hi there, the problem with adding some sand to the area is it is only going to work temporarily as it will wash away pretty quickly. There are several solutions to this common problem.

      1/ Build the area up if you can not remove. Simply concrete in 3×2 timbers around the perimeter making sure they are completely sealed with concrete so nothing can wash under them. You will need to drill some 15 mm cores in the concrete and fill with pea shingle these are to let the water escape. Then simply fill the area up with type 1 if needed (if over 25mm deep) or if you have been able to set the timbers down around the side and only have 25 mm to make up, I would use granite 0-5 mm.
      2/Chip off the rough areas and lay a thicker grass.
      3/Lift the area and completely start the install the install process building up the sub base etc.
      regards

  21. Artificial grass laid onto concrete and after experiencing heavy downpour with no surface puddles appearing we thought the drainage was fine, but then after another downpour a week later we have kinks and bumps in the grass. Is there an issue with drainage or have we done something wrong with the edging?

    • Hi there , not something I have come across before . A few things you can do :-
      1/ lift the grass carefully and may be drill a some drainage cores 15 mm wide and fill with pea shingle which will help water escape .
      2/ Replace grass and sand with kiln dried sand , brushing it in with a broom this will add some weight.
      3/ How is the grass fixed around edge ie have you glued it heavily ? If so this may be causing your issue as it will stop the water from draining through the grass.
      regards

        • Hi yes it sounds to me that because of the gluing around the edge, the rain had really pinned the grass down and there is either excess grass that can’t be flattened out or it’s simply where water was trapped underneath.
          If you can try and lift it carefully without tearing it and then re-trim. Alternatively try sanding it with kiln sand to remove any puffing.

  22. Hi Gavin, great advice! I’m looking to grass out our roof terrace in Spain on top of our apartment. It’s a tiled roof terrace with a slight fall and drainage holes. Can the artificial grass withstand serious high temperatures like 40 degrees? Also, what do you recommend to glue it down?

    Thanks,

    Tony

    • Hi, the answer is simply yes it can!
      There is so much artificial grass used in Spain already on roundabouts, road verges, shopping centres etc.
      The grass is fine in very warm conditions, however I would advise sanding it quite heavily using kiln dried sand brushed in to the pile which will increase the fire retardant capabilities of the area.
      We use aquabond from Envirostik but exterior glues such as hard as nails are fine too.
      Do not overuse. A small bead on the corners and occasionally around the perimeter will allow water to pass through.
      regards

    • Hi yes as long as the area is in pretty good shape ie reasonably smooth and free draining.
      It can be simply laid on top and very lightly stuck down around perimeter leaving gaps for the water to pass through.
      regards

  23. Hi,
    My grass will be bordered all round by a sandstone patio and sandstone blocks. Can I butt the grass up to these or do I still need a timber frame?
    Thanks!

    • Hi yes the stones are simply decorative , the timber is hidden inside the line and acts as a fixing for the grass to stop it being pushed up by wormcasts and to stop it moving away from the edge if the soil moves when it drys out.
      regards

  24. Hi Gavin, great advice I will be following your guide. I was wondering can I use my left over 20mm ballast as a base on top of soil then use a membrane?
    Steve

    • Hi no I’m afraid not . Membrane first , type 1 and then the top layer of granite 0-5 mm if you can get it.
      Firstly the ballast isn’t sufficient as a base layer and secondly if you did use it and lifted the grass in 3 months time , it would simply be soil as the worms would have taken it down into the soil ….would you lay your expensive grass on soil!!!
      regards

  25. Hi Gavin I am planning on laying on top of concrete slab and as it’s so bumpy i have bought a 10mm underlay just wondering how to stick it all down you say leave 1-2 inch gap around perimeter but would what show and a 10mm defect around or does his still apply for 10mm underlay!! Also how do you stick the middle down glue to the underlay?? Thanks mate!!

    • Hi Tom, we have moved away from underlay and simply advised people to go for a thicker grass. Have a look at the post from Melissa below as an alternative way of fitting using what you have as a sub base.
      What you can do is lay the 10 mm underlay out, we simply stuck it together randomly with small bits of gaffer tape to hold it in position, leaving small gaps between each sheet.
      Leave the underlay short approx. 1-2 inches around the perimeter. Then lay your grass carefully on top being careful not to move the underlay.
      Cut your grass to size and stick around the perimeter leaving one foot gaps every few feet so the water can escape.
      You can then sand the grass all over with kiln sand this will pin it down into the underlay. Once the glue has gone off sand around the perimeter to take the edge of the slight lip for the edge of the underlay.
      regards

      • Thankyou for getting back to me gavin great advice thankyou, for future grass laying I will use the advice of no underlay! With this tho if I leave gaps between the underlay will it be felt under foot and visable once it settles! Just unsure how to stick the middle down. Thanks

        • Hi leave a very very tiny gap (10mm ), this wont be felt. You don’t need to stick the middle as the top dress of sand and the weight of the grass will pin it down.
          regards

          • Hi Gavin,
            I’m wanting to lay on top of a concrete patio but there is a 1 inch step up in the middle of the patio. How do I fix grass please, glue?
            Thanks Harry

          • Hi there this a tricky one I’m afraid with no definitive answer. Personally if you can lay the lower grass to the step and stick this will be fine, however the issue is the top step as you need to avoid a trip hazard.
            You can obviously cut along the step line making sure its neat with no over hang and then glue heavily.
            Or if they are slabs maybe go back on slab and angle grind a groove for the grass to be tucked in or if it is concrete how about adding a slab on the top step to cut and stick to. There are a few finishers on line but these are mainly for temporary fitting of grass.
            regards

  26. Hi this might seem a crazy idea but I’m going to ask anyway! I have a garden which is all concrete (large concrete slabs) not good enough to lay artificial grass on and the option of digging it all up isn’t viable as access to remove it is limited. My idea is to build a frame on top of the concrete to make the ground level and ensure there is enough drainage and then either fill on top of the concrete with sand or cover with PVC sheets to make a base for the artificial grass. Is this actually possible as I’m struggling to think of any other way?

    • Hi Melissa, yes this is viable and is something we do as long as you have the scope to build it up, which totally depends on the surroundings. If the answer is yes then follow the steps below.
      – If the patio has gaps in between each slab and the water can drain through it you won’t need to drill 15mm cores into and fill with pea shingle.
      – If you can break the slabs around the perimeter great do it and then concrete in 3 x 2 timbers around edge leaving no more than an inch lip above the patio. By breaking the slabs around edge means you can set the timbers down a bit from the patio and so you wont need as much top layer if not set them on their sides and you may have to top up with type 1 before putting on top layer.
      – When concreting in timbers completely cover all the inside of the timber at the bottom with a mix, this will stop your top layer washing through and causing dipping (don’t forget the water can drain through the gaps in the slabs).
      – I would always recommend granite 0-5 mm as it binds together so much better than sharp sand, but if you can’t, it will have to do however I wouldn’t use more than 1/2 inch of it, top the area up with type 1 and compact, again to stop dipping.
      – Screed the surface once compacted so it is rock hard, flat and level to your side timbers.
      – Fit the grass, if you leave a gap down the side of the timber to the edge (approx. 20-40mm depending on grass depth) you can simply tuck the grass down the back and nail to the timbers.
      – Lightly sand with kiln sand and brush in.
      regards

    • Hi there we only sand a grass with kiln sand if it needs it because it isn’t sitting down onto the base and has some puffing .I would generally take a couple of bags along I think they are 25kg.
      regards

    • Hi, yes both of those will work, however don’t get it on the grass fibres.
      Don’t over stick, in fact use as little as you can because if you ever need to lift it won’t come up and also too much glue will hamper the drainage.
      regards

  27. Hi, I want to put an artificial lawn down and most sites recommend using a bed of sharp sand but I want to be able to put a table and chairs on it to sit on – would the weight cause the table and chairs to press down into the grass and also the sand bed and if so what can be done to mitigate that?

    • Hi, through years of experience a simple layer of sand isn’t sufficient if you want your product to look good for a long time, i.e. not to sink and to become waterlogged in the winter.
      I would always recommend at least 2-3 inches of sub base and compacted in Type 1.
      On top we always use 0-5 mm granite as it compacts up and makes a very hard solid surface to lay on as well as still being porous.
      regards

    • Hi, thanks for the reply, what do you mean when you say “compacted to Type 1”? What depth of 0.5mm granite do you use and can these items be bought from builders merchants?

  28. Hello, I’m planning to fit a single piece of grass (4m by 5m) onto concrete with an underlay. Do I need to leave gaps or holes in the underlay for drainage?
    If you recommend without underlay, how thick would grass need to be? Concrete currently slightly sloped and very bumpy / uneven.
    Thanks

    • Hi we have stopped using underlay as we were using a 5 mm foam and it was working out cheaper to buy a denser grass 35-45 mm.
      However don’t be under any illusion that the grass will cover up the problems of the base.
      If you do use an underlay leave small gaps in between each strip and a 1 inch gap around edge to glue the grass to the base.
      Don’t over glue leave gaps for water to escape.
      Depending on what you want the area to be used for and look like you may want to consider building a base around it using the concrete for a sub base.
      regards

  29. I’m thinking of buying this for our balcony/terrace. There is a concrete base, and there is quite a large dip in the middle what could we do to even this out? Would we need to relay the base again to even this out, or do you have any other suggestions?

    • Hi there you can buy a ‘self levelling compound ‘ which is pretty straight forward to use which will solve this issue, then you can lay the product.
      regards

  30. Hello,
    I’m fitting artificial grass to a long, narrow concrete balcony and will be using a foam underlay. Should I ensure the edge of the foam underlay reaches the edges of the balcony and glue the edges of the grass to the foam underlay? Or, should I leave a small gap around the edge of the foam underlay and glue the edges of the grass to the concrete balcony?
    Thanks!

    • Hi there , good point .
      We usually lay out the foam and use gaffer tape to hold it together so it doesnt curl up whilst you are fitting, we leave and 1-2 inch gap around perimeter .
      The weight of the grass will hold the foam in place then simply stick around perimeter .
      We leave gaps in our gluing to allow the water to get out.
      regards

  31. Hi there, I have a concrete are designed for a conservatory so is very flat and puddles in two locations. I want to put artificial grass down and I bought the foam to aid cushioning as the area will be for a toddler. Read your piece and the foam does not seem to let liquid through. Should I put holes in the foam and drill where it puddles also?

    • Hi this year I have moved away from underlay as much as I can. I personally believe it is easier to buy a denser, deeper and thicker grass than adding a 5mm underlay that will slow down the drainage.
      Simply drill 15mm cores and fill with pea shingle in the puddling areas to improve drainage.
      Do not over glue the grass as this will stop the flow of water trying to pass through it.
      regards

  32. Hi
    Most underlays seem to be expensive for artificial grass. I have lots of underlay left over from laminate floor installation, would this be ok to use instead?

    James

    • Hi there, the underlay I have been using is a 5mm foam underlay however it is pretty dense, hard wearing and non absorbent.
      Laminate floor underlay is very flimsy and wont really serve any purpose outside, so sorry there is no cheap fix.
      regards

    • Hi we generally use a 5mm foam underlay which we simply roll out leaving a 1-2 inch gap around the perimeter.
      The grass can then be simply fitted and stuck intermediately around the edges to the concrete.

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