# Garage Floor Repair



## LambCrafter (3 Apr 2021)

Hi UKworkshop members,

Would welcome your advice on how best to repair the floor in my garage. I would like to add wheels to my work benches and storage units but the rough section of the floor would make moving them around a bit harder. The photos hopefully show the section of rough floor.

IMG1 shows the section of rough floor. It's about 20% of the width of the garage and runs along where the garage joins the house. Over time it looks like the floor has broken up.
IMG2 shows the step down from the main concrete slab to the rough area.
IMG3 shows the meeting of the main concrete slab, a non-broken up area, and the broken up area.

My thinking is to use a SBR/water mix to bind the three areas together and then use self levelling compound to bring the level of the rough section up to that of the main concrete slab. 

Is this a reasonable approach?, or should I look at using self levelling for the whole of the floor area?, or use another method/materials? 

Thanks in advance for your help.

Colin

(P.S. Will be attending to the gaps in the garage doors as well)


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## LJM (3 Apr 2021)

Apart from the surface finish, is the concrete sound?


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## LambCrafter (3 Apr 2021)

LJM said:


> Apart from the surface finish, is the concrete sound?


The main concrete slab is sound. I've removed the loose bits from the broken up area so I'm thinking that I need to first bond/seal it before doing anything else?


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## Old.bodger (3 Apr 2021)

This thread might help









Self levelling compound on a tamped concrete garage floor


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...




www.ukworkshop.co.uk


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## LambCrafter (3 Apr 2021)

Old.bodger said:


> This thread might help
> 
> 
> 
> ...


Thanks for the link. I looked through the workshop build post before asking for advice. Looks that the link you’ve provided was ‘hiding’ in the General Woodworking section.


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## LambCrafter (3 Apr 2021)

LambCrafter said:


> Thanks for the link. I looked through the workshop build post before asking for advice. Looks that the link you’ve provided was ‘hiding’ in the General Woodworking section.


Looks like the way to go is: seal with SBR/water mix, fill the broken up part with Stopgap Graded Aggregate (as largest ‘depth’ is more than 10mm) and then use Stopgap 300 HD over the whole area. Followed by good quality floor paint.


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## Old.bodger (3 Apr 2021)

That looks about it. It won’t be cheap but you only want to do it once. The Stopgap products are good. Any questions and the Stopgap tech department is very helpful.
Make sure that you consider/ review the damp proof membrane situation , if there is none then you need to consider an epoxy dmp in the coatings.


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## LambCrafter (3 Apr 2021)

Old.bodger said:


> That looks about it. It won’t be cheap but you only want to do it once. The Stopgap products are good. Any questions and the Stopgap tech department is very helpful.
> Make sure that you consider/ review the damp proof membrane situation , if there is none then you need to consider an epoxy dmp in the coatings.


Thank you for the help and I’ll check the dpm before proceeding. I’ve been reading more on the internet and it looks like painting the compound is not typically recommended. So maybe rubber matting or tiles is the way to go. Only plan to do this once so need to get is right.


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## manglitter (4 Apr 2021)

You could use a pva/water mix to seal everything, then deep base self leveling compound to bring the low areas up, pva again then regular thin set self leveling compound all over to finish?


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## Fergie 307 (5 Apr 2021)

Self levelling compound is not really suitable for a garage floor, it's not really hard enough. You will find that localised loads, like the legs of machines and so on will readily make holes in it. You will also find it hard to get your old floor clean enough for the compound to bond properly, then local loads will cause it to break up from the underlying floor. A neighbour of mine did exactly this and now has loads of missing chunks where the compound has separated from the underlying floor and broken up. I think this happened the very first time he parked his bike on the new floor, up onto the centre stand and bingo, two holes in the floor! He had just wanted to get rid of tamping marks. A couple of people gave the same advice I did, hire a floor grinder. But the compound was easier apparently. 
I would have thought your best bet is to remove the top couple of inches of the broken area, then assuming what you are left with is sound, seal with PVA and bring it up level with a fine aggregate concrete. To remove the broken area use a disc cutter to cut lines a couple of inches apart to the depth you want to remove, then you will find the sections between the cuts will break off easily. Once you start cutting it you will get a good idea of the soundness of the material. If it is weak and breaks up easily you might have to remove it all.


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## Fergie 307 (5 Apr 2021)

While we're on the subject a good way of removing tamping marks when you are laying new concrete. Get a roll of plastic dpc. Lay it across one end of your newly laid concrete and get a person on the either end of it. Curl the front edge up slightly, like the end of a ski. Now, keeping it good and tight on the framing, just drag it along the surface. If the concrete is still nice and wet you will get a really smooth finish, almost as good as using a float.


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## Robbo60 (5 Apr 2021)

Concrete still cold and hard on feet. I put 18mm OSB on my floor (got for nothing) big improvement. B & Q got rubber tiles at the moment 600 x 600, pack of 6 for £14


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## shed9 (5 Apr 2021)

As pointed out in last years thread as this is often missed but needs stating again, self levelling compound is not self levelling. It has to be one of the most inaptly named building products out there. Also generic self-levelling compound is merely a substrate for another floor covering anyhow.

Given the area is already shuttered (other than the door openings) like Fergie 307, I'd be tempted to clean the area and pour a fine aggregate mix over the entire mess. Patching floors rarely works in the long term if at all. Most concrete firms have small delivery mixes these days that will actually not be that much more than if you bought the materials and mixed it yourself. Just do the prep work, order the mix and point them in the right direction when they turn up. Keep the tea and hobnobs flowing and they will work with you within their timeframe. Pour as deep as you can get away with, allowing for budget and head height and hire a concrete poker. Pokers will make all the difference and pretty much almost self level everything for you as well as doing the tamping work and removing air. I have laid 4x16m slabs with pokers and been level to 1/4 inch across the entire mass. Its Harry Potter magic territory seeing them at work. After hiring one the first time around I went straight out and bought one, I don't do that much concrete work but it had paid it's way many times over. Seal it and then cover or paint.

It's not as expensive as you think and probably involves the least amount of work for the most returns on floor finish.


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## LambCrafter (5 Apr 2021)

I’m confused now. The OP last year mentioned the manufacturer stated the 300 HD was OK for a garage floor and having a car/200kg machines on it. It doesn’t sound like a generic compound.

I also thought PVA is water soluble so when a mix containing water is poured onto it the seal can be degraded. SBR, although costing a bit more, keeps the seal and gives more working time as water is not drawn out of the mix into the floor. Maybe I’m wrong with what I’ve read.

Anyhow, I have an email to the F Ball tech department over the weekend for advice so I’ll see what they say.


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## Old.bodger (5 Apr 2021)

Yes, I have been trying not to comment again, but.......

Generic compounds from the builders merchants are NOT suitable, stick with the recommended products. PVA is NOT suitable, there are again correct primers and DPM products. Top surface, there are two pack epoxy products that work. This is the result of doing this type of job for nearly 30 years.......but others may know better !!!!!!


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## shed9 (5 Apr 2021)

LambCrafter said:


> I’m confused now. The OP last year mentioned the manufacturer stated the 300 HD was OK for a garage floor and having a car/200kg machines on it. It doesn’t sound like a generic compound.


300HD isn't a generic compound, my own reference was to the original post on this thread and the comment of self-levelling compound, apologies if it was my post that caused confusion. However, be aware that F Ball specifically state that their 300HD product is not purposed as a wearing surface, more as a substrate. Doesn't mean you can't use it for the purpose of what you want, just that the product isn't necessarily designed for that. 
Personally I wouldn't consider any self-levelling compound as a final floor layer but that's based on my own experience and that in itself doesn't compare to the experience of others on this thread. 

Ultimately, it all depends your skillset, experience of using and applying screed / concrete mixes and of course your expectations of the final job. I often see too many people use self-levellers as a 'cheap' fixit to a bigger problem which eventually results in entirely new floors being cast is all.


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## LambCrafter (5 Apr 2021)

shed9 said:


> 300HD isn't a generic compound, my own reference was to the original post on this thread and the comment of self-levelling compound, apologies if it was my post that caused confusion. However, be aware that F Ball specifically state that their 300HD product is not purposed as a wearing surface, more as a substrate. Doesn't mean you can't use it for the purpose of what you want, just that the product isn't necessarily designed for that.
> Personally I wouldn't consider any self-levelling compound as a final floor layer but that's based on my own experience and that in itself doesn't compare to the experience of others on this thread.
> 
> Ultimately, it all depends your skillset, experience of using and applying screed / concrete mixes and of course your expectations of the final job. I often see too many people use self-levellers as a 'cheap' fixit to a bigger problem which eventually results in entirely new floors being cast is all.


The original post on this thread was mine and I was kindly pointed to a previous thread that mentioned 300 HD. I’ve got confused because people started talking about ‘generic’ levelling compound after I had already started mentioning 300 HD, which looks to be ‘specialist’.

As mentioned in one of my posts I have already emailed F Ball’s tech department so hopefully I will receive specific advice/recommendations based on their own product, application, and surface treatment.


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## Spectric (5 Apr 2021)

There are two pack resin floor coverings that will level and provide a hard glass finish but I dont think they are cheap.


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## Fergie 307 (5 Apr 2021)

Just to clarify. Old Bodger is absolutely correct that PVA is completely unsuitable as damp protection, apologies if I appeared to be suggesting that. It is very good at sealing a porous surface, and helping to get a good bond between your old concrete and the new top skim. You should of course make sure there is an adequate damp proof layer, or use a product specifically designed for this If not. My concern would be that if the material breaking away is part of the slab, as distinct from a top skim, then it's probably the same all the way down, and ought to be removed. As to the suitability of specialist coatings, it depends what you want to do with it. I need a floor that will take trolley jacks and similar, so very high loads over a tiny area. I have yet to see a self smoothing thin layer product that can stand up to that without disintegrating.


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## shed9 (5 Apr 2021)

LambCrafter said:


> The original post on this thread was mine and I was kindly pointed to a previous thread that mentioned 300 HD.


I got that bit


LambCrafter said:


> I’ve got confused because people started talking about ‘generic’ levelling compound after *I had already started mentioning 300 HD*, which looks to be ‘specialist’.


But hadn't seen that bit


LambCrafter said:


> As mentioned in one of my posts I have already emailed F Ball’s tech department so hopefully I will receive specific advice/recommendations based on their own product, application, and surface treatment.


I would be interested in their advice relevant to your specific requirements. As already mentioned by myself, their own literature is quire specific in noting that 300 HD is not a wearing surface.

For what it's worth, my main shop is a concrete slab which is fairly level and relatively smooth. It's not great but certainly a continuous slab however I still have issues with large weighted wheeled machinery with any slight deviation or divet on the floor itself. I'm at the start of two new builds to replace the current workshop and have opted for a ply floor based on my experience of direct concrete contact.


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## Fergie 307 (5 Apr 2021)

Not sure I understand. If you are laying a new concrete floor then just get it properly flat and smooth, then you have no need for the extra expense of putting ply on top. If like me you get back pain from standing on it then I sympathise. I have a good quality yoga mat in from of my lathe, big enough so you don't risk tripping over the edges. Makes a surprising difference when you are standing there for hours at a time.


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## LambCrafter (6 Apr 2021)

I received a phone call from F Ball's tech department this morning regarding the questions I asked via e-mail. Great service based on that it was a bank holiday weekend just gone.

From the conversation I can advise (*for my application*) that:

Stopgap 300 HD is suitable and is fine for parking a car on and having wheeled workbenches moving over it (see paint point below).
The recommendation is to have a thickness of at least 5mm and using Stopgap aggregate to fill the lower strip at the edge prior to pouring is OK.
SBR the area before adding the aggregate and pouring the 300 HD.
The resulting floor can be painted (at least 2 coats recommended) with a water based epoxy garage floor paint.
I now have the way forward but having looked at the garage more closely I feel (for me) it would be wise to do some fillet pointing around the outside edge as it looks like this may be a source of some slight dampness limited to the corner next to the door (thanks again to Old.bodger for drawing my attention to this). I'll do the pointing and check on the situation and consider if a dpm coat is preferable.


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