Crumbling cement floor in workshop

[Seascaper]

Cheapskate builders, the concrete floor is crumbling. Sealed and painted, recurs where foot traffic.

How good are the 'expensive' Rust-oleum epoxy products? Worth it?
Any idea how to get better adhesion to existing concrete please?
I've about 10 small areas, with poor edging (could be made deeper).

Hello,
One can get a very could product used for levelling floors, comes in a powerder for, rather like cement in appearance but you mix up to a cream consistency in a wheelbarrow or bucket then pour onto your surface. It soon dries to perfect flat finish and can be used on concrete floors. It is called something like floor levelling compound and one DS an use it over a large or small area.
Regards

 

[baldkev]

Hi dave, the advantage of the epoxy paint is its strength, as it wont wear through easily, so as long as it bonds to the substrate,it should help hold things together a bit. It wouldn't cure any weak crumbly areas, but it might be enough to hold it the top surface together. Is there any disadvantage to overboarding with 12mm ply? If your problems persist,you could cover the exposed floor ?

Latex can be a fairly hard finish and i have done a floor in a garage turned into an art studio with latex as the finished floor. Its holding up well after a couple of years
Edit: I'd imagine the weight of a cast machine would still do damage.

 

[pe2dave]

Hi dave, the advantage of the epoxy paint is its strength, as it wont wear through easily, so as long as it bonds to the substrate,it should help hold things together a bit. It wouldn't cure any weak crumbly areas, but it might be enough to hold it the top surface together. Is there any disadvantage to overboarding with 12mm ply? If your problems persist,you could cover the exposed floor ?

Latex can be a fairly hard finish and i have done a floor in a garage turned into an art studio with latex as the finished floor. Its holding up well after a couple of years
Edit: I'd imagine the weight of a cast machine would still do damage.

"as long as it bonds to the substrate" I think that's the issue Kev? The paint 'isn't' bonding.

A 12mm ply floor? Would it stay in place? Stay flat?
a) I suspect not.
b) I can't empty the workshop, lay a floor and reload it.

If I could, I guess a professional fix, ie. scrub the paint, clear down to 'firm' concrete, overpour with self levelling or something would be the answer.

Sadly I'm too old to even consider that.

 

[baldkev]

Well you could pour a 10mm layer of epoxy over the exposed area, just put a little barrier around the edges you cant go under, sealed with silicone. That'd 'probably' be thick enough to resist breaking and it'll be fully supported by the weaker stuff underneath.

As for ply, like i said, itd be the exposed floor areas. You simply fix it down, probably turbo screws.
One thing that hasnt been asked is if its concrete or cement screed? If it had lumps of aggregate, its concrete, if sandy, its just a screed and the concrete should be under the screed of 2 to 3"

 

[pe2dave]

Well you could pour a 10mm layer of epoxy over the exposed area, just put a little barrier around the edges you cant go under, sealed with silicone. That'd 'probably' be thick enough to resist breaking and it'll be fully supported by the weaker stuff underneath.

As for ply, like i said, itd be the exposed floor areas. You simply fix it down, probably turbo screws.
One thing that hasnt been asked is if its concrete or cement screed? If it had lumps of aggregate, its concrete, if sandy, its just a screed and the concrete should be under the screed of 2 to 3"

That would be proud of the existing concrete Kev?

Screed, since it has lumps of aggregate (made it hard work with the 'grinder' on angle grinder).

I'm of an age where a patch will do, no more 'big jobs'

 

[baldkev]

Yes it would be on top of the concrete, but fast and easy.....

Hope you get it sorted whichever route you go

 

[johna.clements]

My slab has a 50mm thick concrete screed, which is about as thin as you can go with concrete with 20mm aggregate. If I had used sand and cement for the screed I could have halved that.

 

[Woodwork Journey Dean]

My garage/workshop floor concrete was horrific, my cheap and easy solution was to get a load of thick second hand laminate floor boards for cheap or free on marketplace, throw down a little underlay on the really bad bits, and when I had enough cover 90% of my floor with them. Especially with benches and machines on then they don’t really move much.
It’s been fine for a good 8 months I would think

 

[MikeJhn]

Fundamental difference between Epoxy and Polyester resins is the curing of the Polymer chain, Epoxy has a Catalyst that binds the chains to each other and leaves itself behind holding the chain together, hence the need to mix correctly otherwise bubbles of Catalyst can be left behind and the cure will not be complete and the strength will be compromised, epoxies will not cure well when water is present.

Polyester resins have the same type of Polymer chain but the Catalyst is an exciter that draws the chain together, and moves on, hence the small amount of Catalyst required and the shrinkage experienced with them, the heat generated and their tolerance to water. but they are much weaker that Epoxies. They will also melt Polystyrene and the like, so test before use.

Both Epoxies and Polyester Resins are only as good as the surface they are being applied too and any loose material must be removed and a firm surface found or its a waste of time and monies.

 

[MikeJhn]

One thought, if you have a compressor, hire or buy a needle gun and use that too break up the loose areas and use Epoxy to make good the floor, or a Polyester if it is only subject to foot traffic and only a small area and not too deep, the heat generated by a Polyester can be substantial and the shrinkage can also be a problem with the surface cracking, Polyesters have their place, but not in construction that is meant to last and of an exposed area.

 

[pe2dave]

One thought, if you have a compressor, hire or buy a needle gun and use that too break up the loose areas and use Epoxy to make good the floor, or a Polyester if it is only subject to foot traffic and only a small area and not too deep, the heat generated by a Polyester can be substantial and the shrinkage can also be a problem with the surface cracking, Polyesters have their place, but not in construction that is meant to last and of an exposed area.

Good idea... except using a grinding disk the dust!!!
Having seen air needle guns at work on a ships deck, they are very effective! Because of the poor
state of the concrete, I've been peeling it off (mostly) with a paint scraper!
I have a small compressor, guessing a needle gun might be high air use? mc mart, 4cfm
I'll have a look for future use, thanks Mike.

 

[pe2dave]

One thought, if you have a compressor, hire or buy a needle gun and use that too break up the loose areas and use Epoxy to make good the floor, or a Polyester if it is only subject to foot traffic and only a small area and not too deep, the heat generated by a Polyester can be substantial and the shrinkage can also be a problem with the surface cracking, Polyesters have their place, but not in construction that is meant to last and of an exposed area.

Lessons learned:
Starting point, poor concrete floor crumbling, 25 years old, existing floor paint flaking in spots, some larger areas with heavy footfall / usage.
(obvious?). Clean off back to good baseline (remove flaky paint, dust / chippings). [1]
a) Apply bonding - cementone seems to work. repaint, or if bad apply [?????? *[2]], then repaint.
b) as above, try above: Epoxy or (what is) Polyester (- not a shirt?) 'filler' to level the surface??? tbc
[1] I'm looking at @MikeJhn needle gun. Less dust than the 'grinder' head suggested.
[2] What to 'paint' a decent base/concrete with? I'm thinking almost liquid cement/ mortar? What are the options where I need to build up say 2-5mm?

Currently waiting for floor paint to dry, ready for second coat.

 

[valvebounce]

I would cut the holes about 25mm deep with square sides.Use blocklaying grit (fine)
with just cement,if you are feeling ambitious,use a 3/1 water mix with waterproof pva.
Bostic make one for floor screeding,but a decent waterproof pva will work.(normal pva melts with dampness.)Avoid feathering the holes,it will snap at the edges and you will be back to square one.

 

[valvebounce]

I would cut the holes about 25mm deep with square sides.Use blocklaying grit (fine)
with just cement,if you are feeling ambitious,use a 3/1 water mix with waterproof pva.
Bostic make one for floor screeding,but a decent waterproof pva will work.(normal pva melts with dampness.)Avoid feathering the holes,it will snap at the edges and you will be back to square one.

 

[pe2dave]

No way @valvebounce - It's solid within 2mm of the surface.
Point taken about feathered edges, hence my questions.
I'm using cementone, which is pva for bonding.

 

[baldkev]

No way @valvebounce - It's solid within 2mm of the surface.

In that case, wouldnt a floor scraper be an idea? Like a big mutt.

Yep needle guns need loads of cfm......

 

[MikeJhn]

b) as above, try above: Epoxy or (what is) Polyester (- not a shirt?) 'filler' to level the surface??? tbc

Explained the difference in post 49 above, you can tell the difference by the amount of catalyst required, Epoxy has equal parts of resin and catalyst and has to be well mixed, Polyester needs a very small amount of catalyst and is not so critical on the mixing.

 

[MikeJhn]

3 cfm @ 90 psi: Air Needle Scaler | SA51 | 1 year Warranty | Sealey

 

[pe2dave]

Explained the difference in post 49 above, you can tell the difference by the amount of catalyst required, Epoxy has equal parts of resin and catalyst and has to be well mixed, Polyester needs a very small amount of catalyst and is not so critical on the mixing.

(for me) you explained it as to a chemist! How might a builder describe them please?
Any trade names please Mike?
And (guessing your preference for epoxy) - suitability for a 'thin' layer repair? say 2-3mm?

 

[MikeJhn]

Think of Araldite for Epoxy and Davids Isopon for Polyester, giving any trade names for this application is not possible, as I am out of touch with the latest products.

Trying to repair 2-3mm is like trying to use a sticking plaster to cover a hemorrhage it will not work.