Self levelling compound on a tamped concrete garage floor

[RogerM]

I'm contemplating grasping the nettle and to try to put a smooth surface on an existing tamped concrete floor in my garage. The garage is attached to our house, has a damp course and I also think there will be a damp proof membrane under the floor slab as I have no issues with damp. The main problem is the unevenness of the floor which makes moving machinery around very difficult. I'm thinking in terms of using a self-levelling compound, but most advertise that this is only to prepare a surface for a floor covering, and is not a final surface.

Some people recommend covering with interlocking plastic tiles, and others a two part epoxy floor paint. Screwfix do Mapei Ultra 1210 at a sensible price, but it is unclear whether this would be up to the job if just painted. Ideally I want something relatively slow setting as I don't want to have to work like a paperhanger in a gale to get it all down in one coat. I have 30 sq metres to level.

Does anyone with any practical experience of using these products as a final surface in a workshop? And if so, what products did you use?

 

[Max Power]

As you say self levelling compound is a substrate to prepare for a covering, tiles etc. It wouldn't last long dragging machinery around on it.

 

[RogerM]

Those were my thoughts too Max. Favourite at the moment is to level it with Mapei Ultra 1210 and then to cover it with floor grade interlocking chipboard (about £200) or interlocking plastic tiles - but that would be close to £1,000

 

[screwpainting]

I would look into surface grinding/polishers, just machine hire and elbow grease.

 

[large red]

If you are meticulous with prep and prime the floor with a diluted SBR primer (not PVA) prior to laying the self leveling material you will get away with painting the floor, if you use a quality 2 part floor paint.

 

[mbartlett99]

I used latex screed from Jewsons 10 yrs ago and it still looks perfect so I'm not sure what the issue might be. It was a tricky job especially on a hot June day - you have to move like the devils after you. My floor was all over the place and as rough as a badgers arse so aI needed a fair amount of compound on it. If I were doing it again I'd want a 2nd person or a small cement mixer.

If you go ahead do it on the coldest day you can and add a little more water than they say. I finished it with floor paint and it still looks fine; my combi weighs 500kg and the bandsaw 200 so it can take the load.

 

[Old.bodger]

I spent nearly thirty years laying this type of product. Firstly be aware that it is self smoothing don’t think of it as self leveling !

Avoid any that are water mix. F ball and Co do a good selection and they come with their own gauging liquids. Use the correct primer and follow the instructions. Throughly mix with a powered paddle in a large container. Don’t be mean with it, it can be feathered out but you loose the self smoothing properties. Use one that is rated for fork truck traffic, lay at min. 5mm thick, prime first and use a spiked roller. Do the whole floor in one hit, keeping a wet edge, you may need a second person mixing, (so two containers to mix in etc ) and if you can get a third person on the spiked roller.......

If the floor has any surface contamination/ or is polished/ power floated you may need to scabble first ( hope not!)

Once it is really dry, apply epoxy floor finish.

It will last for years if done correctly.

 

[RogerM]

I spent nearly thirty years laying this type of product. Firstly be aware that it is self smoothing don’t think of it as self leveling !

Avoid any that are water mix. F ball and Co do a good selection and they come with their own gauging liquids. Use the correct primer and follow the instructions. Throughly mix with a powered paddle in a large container. Don’t be mean with it, it can be feathered out but you loose the self smoothing properties. Use one that is rated for fork truck traffic, lay at min. 5mm thick, prime first and use a spiked roller. Do the whole floor in one hit, keeping a wet edge, you may need a second person mixing, (so two containers to mix in etc ) and if you can get a third person on the spiked roller.......

If the floor has any surface contamination/ or is polished/ power floated you may need to scabble first ( hope not!)

Once it is really dry, apply epoxy floor finish.

It will last for years if done correctly.

Thanks. Nice to hear from someone with practical experience. F Ball & Co Stopgap 1200 Pro or Stopgap 800 Wearcoat look like the best products from their range for this type of application. However, I have about 30 sq m to do, and only me and my wife to do it. Time is not money for us, so is there some sort of retardent that can be added to extend the workable time? Given that it can be walked on in an hour, I can foresee us running into trouble. Or maybe just do it on a cold day - but I'll also need the weather to be reliably dry as everything will have to stay outside for one night at least.

For 30 sqm I would need approx 10 bags, so presumably you would divide the floor into 3sqm sections with a moveable batten "dam" to define the edges to ensure even coverage, and then move the battens for each section, using the edge of the previous section as the other edge, if you see what I mean?

 

[Old.bodger]

Roger,
The Stopgap 800 looks the best for you, interestingly their product have moved on since I stopped working with them and I see that this is now water mix! (I take back my comment about avoiding water mix). I always found their tech department very helpful if you need them. No retardant that I know of but you can push the water content up to 5 ltr, that will help.
The primer is essential to get a good flow so make sure that is coated well. I can’t see that you couldn’t do it in ‘bays’ so long as you accept that you WILL see them afterwards how ever good you are with a float trowel. You will need to cover the ‘wet’ side of your dam with brown parcel tape, to avoid adhesion, and also seal to avoid leakage, a bead of ordinary silicone builders seal will do no harm. It is worth looking around the perimeter of the floor, and perhaps sealing around where the subfloor was cast inside the brick walls ( making assumptions here) as this stuff is quite liquid and it is very frustrating to have it all start to disappear down a crack , giving you a sink hole. Likewise seal any cracks in the subfloor. Also think about fixing the middle of your dam to stop it bowing with the weight of the compound behind it. Last thought is about mixing, firstly don’t try mixing ‘ part bags’ you need a container bigger than a bucket, I used to use 25ltr drums scrounged from the local garage that had had screenwash etc in and cut the lid off, put the 5 ltrs of water in first, get it moving with the drill whisk, and TRICKLE the powder in ........be prepared and dressed for splashes! Then dump it on the floor, spread quickly with a big float trowel and roll with the spiked roller........AND LEAVE IT ALONE !

Regards

Jim

 

[RogerM]

Roger,
The Stopgap 800 looks the best for you, interestingly their product have moved on since I stopped working with them and I see that this is now water mix! (I take back my comment about avoiding water mix). I always found their tech department very helpful if you need them. No retardant that I know of but you can push the water content up to 5 ltr, that will help.
The primer is essential to get a good flow so make sure that is coated well. I can’t see that you couldn’t do it in ‘bays’ so long as you accept that you WILL see them afterwards how ever good you are with a float trowel. You will need to cover the ‘wet’ side of your dam with brown parcel tape, to avoid adhesion, and also seal to avoid leakage, a bead of ordinary silicone builders seal will do no harm. It is worth looking around the perimeter of the floor, and perhaps sealing around where the subfloor was cast inside the brick walls ( making assumptions here) as this stuff is quite liquid and it is very frustrating to have it all start to disappear down a crack , giving you a sink hole. Likewise seal any cracks in the subfloor. Also think about fixing the middle of your dam to stop it bowing with the weight of the compound behind it. Last thought is about mixing, firstly don’t try mixing ‘ part bags’ you need a container bigger than a bucket, I used to use 25ltr drums scrounged from the local garage that had had screenwash etc in and cut the lid off, put the 5 ltrs of water in first, get it moving with the drill whisk, and TRICKLE the powder in ........be prepared and dressed for splashes! Then dump it on the floor, spread quickly with a big float trowel and roll with the spiked roller........AND LEAVE IT ALONE !

Regards

Jim

Jim - you are an absolute star! I was thinking only leave the dam in place until the mix has started to set sufficiently to hold its shape, and then remove it and pour the next batch to help with bonding along the edge. I'm not bothered about the shape of the bays being visible so long as I don't have a step between them. There are no significant cracks, and the surface is dry with no contaminants - this garage has never seen a car in it, it's as much as I can do to fit the bikes in between the woodworking toys.

When it comes to the edge by the garage entrance, can this stuff be feathered down to nothing to form a ramp, or should I just accept that there may be a 5mm step, which even I would find difficult to trip over?

And when assessing the surface after all the toys have been cleared, would you be tempted to fill the deeper hollows (where there were edges to the different mixes in the tamped floor slab) or just go straight in with the Stopgap 800 - after sweeping, vac'ing and priming of course?

I've already got some 40litre flexible buckets for mixing. Sounds like we have the beginnings of a plan!

 

[Old.bodger]

Yes you can feather the edge out.
Good luck !

 

[AJB Temple]

This is a really helpful thread. Should be retained somewhere as a "how to".

 

[Neil S]

Good luck Roger, I hope it goes well.
I've always wanted to do this but have been put off by the thought of emptying out the whole garage in one go and storing everything outside while it's done.

Let us know how it goes, perhaps you will inspire others by your success. =D>

-Neil

 

[RogerM]

Thanks Neil. I'm in the middle of refitting the bathroom at the moment so it will have to wait a week or two. But it's definitely a project for some time this summer. Back in the winter, I wanted to move my planer thicknesser to a position where I could feed long pieces of stock through it. The wheels got stuck in a rut, and then when I pulled harder it came in a rush and went over my toe - all 165 kilos of it! So that was the last straw! It will be done!

 

[RogerM]

Following the help offered here, I contacted F Ball tech dept and what a helpful guy I found! In his opinion, whilst Stopgap 800 would be the Rolls Royce solution, it is not cheap, and is designed for factory and commercial warehouse applications so probably overkill for a domestic workshop. He recommended Stopgap 300 HD which is considerably cheaper and certainly strong enough to take a car and to wheel around a 200kg machine over it. Of key importance is priming the surface. This not only helps adhesion, but also keeps the product workable for longer. He also suggested applying the Stopgap 300 HD on a cool day, and if doing it in the summer start early in the morning before it gets too warm. Temperatures much above 20C would make spreading a large area "challenging".

I asked about how to tackle the entrance to the garage, and could the Stopgap 300 HD be feathered to an edge? Yes it can, but a better solution would be to cut a shallow groove (about 5mm with a disk cutter, and chase back the floor for a few cms on the inside so that not only would I have a straight edge which would look better, but a 5mm thickness could be maintained right up to the edge which would help the structural integrity of the floor. Sounds like we have a plan!

 

[shumphr1]

How did it go Roger? I too have the same job ahead of me on a 5m x 6m garage tamped concrete base with a log cabin on top.

 

[Terry - Somerset]

If the self levelling compound is being put down only to form a decent base for a further covering, you may like to reflect on:

• how bad is the existing surface - is it broadly flat but rough, or wavy and rough
• what is the further covering - paint or lino would pick up every lump or bump in the tamped base, 25mm chipboard would be fine directly on the tamped floor providing it was fundamentally level

 

[Fidget]

How did it go Roger? I too have the same job ahead of me on a 5m x 6m garage tamped concrete base with a log cabin on top.

(Not Roger)

I had a tamped floor in my workshop built about 4 years ago before I found UKW and used primer then self levelling compound followed by floor paint from Screwfix. I haven't had any problems.

PS I don't live far away, Pm me If you need more info

 

[baldkev]

Some great advice from old bodger. Most people add a bit extra water for better flow, but i cant honestly day if it weakens to finished floor surface ( it may do )

I did this one early this year, 2 of us, about 10mm thick in most places. Spiked roller essential and you can get spiked platforms to strap on your boots. In this one, we had a row of units going down one side, so to give access and reduce material, we left a 500mm strip.

You will see some plywood bases in the piks. I use these to set heights to aim for as i work back. They have screws going down thru for the ply to be held off the floor by whatever height is required. I use a laser level, set the first one to height, measure off it to the laser, then simply set up the other blocks using the same measurement down from the laser.
There was probably 16 or so in the garage spread around and i used them as a simple way to make sure i didnt under/ overfill any areas. Its a very level floor. As old bidger said, its not actually self levelling, you can create a fall with it if you wish. I did a rough pour to take out the lumpiness and fill a couple of bad areas, and to make the final coat an even thickness for drying etc.

 

[RogerM]

How did it go Roger? I too have the same job ahead of me on a 5m x 6m garage tamped concrete base with a log cabin on top.

Sorry for the delay in responding. I've been away and not checking this forum. The long and short of it is that I never got around to it! Other priorities arose in spring, and during the summer temperatures are too high to do a decent job on a large area when working on my own. Who am I kidding? 90% of the reason is that I kept looking at the 32 years of accumulated stuff in the garage and couldn't face having to move it all out! Since then I've started suffering from rheumatoid arthritis in my wrists and so I'm not looking for additional heavy work over and above that which is essential. If I were to do it though, I would use the Stop Gap stuff mentioned above, and probably go down the Stop Gap 800 route, which although is probably overkill and more expensive, would be guaranteed to be up to the job, whereas the Stop Gap 300 may need a covering of some sort.