How to stop concrete from chalking?

[Barking Mat]

I don't think the walls will move.

My current problem is my drive from the road. I put it in 3 years ago, and over the drainage ditch next to the road I put in a plastic 40 cm industrial plastic pipe, you know black corrugated thing, back filled with hard-core etc. And then I 'concreted' over it. Ok for cars and vans. But not artic lorries and cement mixers, which reduced it to hard-core / rubble, and over months of standard car use, you get troughs and puddles.

So I'm going to wait for the last concrete floor to be poured and reattack it as it's not serious, but does pee me off. Normally I just get leftover cement slurry and pour it on, but obviously I didn't compact it enough for a 40 ton lorry. Or I should reinforce it with rebarr mesh, just more money....

 

[pandemonium123]

I don't think the walls will move.

My current problem is my drive from the road. I put it in 3 years ago, and over the drainage ditch next to the road I put in a plastic 40 cm industrial plastic pipe, you know black corrugated thing, back filled with hard-core etc. And then I 'concreted' over it. Ok for cars and vans. But not artic lorries and cement mixers, which reduced it to hard-core / rubble, and over months of standard car use, you get troughs and puddles.

So I'm going to wait for the last concrete floor to be poured and reattack it as it's not serious, but does pee me off. Normally I just get leftover cement slurry and pour it on, but obviously I didn't compact it enough for a 40 ton lorry. Or I should reinforce it with rebarr mesh, just more money....

If you want to be good for 40 ton truck.
Dig out 200mm.
Put in 100mm hardcore & compact with 1 drum roller.
Put in next 100mm & compact.
Then 100mm c35 minimum

Pour c35 grade reinforced with a393 mesh in bottom 25-35mm lifted with spacer blocks.
Mesh should be over lapped minimum 100mm & wire tied together.

 

[pandemonium123]

Remove the plastic tube it is flexing & deforming causing subsidence. Replace with concrete sectional tube.

Or cast the plastic tube you have in concrete.

 

[pandemonium123]

From what I have gathered from the hive mind of this forum, expansion joints are only for massive areas. My kitchen is 55m2 and back room 75m2. Doesn't need expansion joints. Might want to look at steel reinforcement mesh if you're driving vans or lorries over it.

Yes, expansion joints are just cut in from my understanding.

Expansion joints are cut in as soon as possible after pour. They ae designed not for movement but to force the slab to crack where you want it to & not just anywhere.
The joints are then filled with mastic or epoxy.

Proper expansion joints are the fibrous boards laid vertical around the room or where required to allow true expansion & contraction of the concrete.
Although not really needed these days when it's an insulated slab with 50mm of foam around the edge to prevent cold spots

 

[Pete.]

If you want to be good for 40 ton truck.
Dig out 200mm.
Put in 100mm hardcore & compact with 1 drum roller.
Put in next 100mm & compact.
Then 100mm c35 minimum

Pour c35 grade reinforced with a393 mesh in bottom 25-35mm lifted with spacer blocks.
Mesh should be over lapped minimum 100mm & wire tied together.

Standard lap for mesh is 40 x D so A393 mesh being 10mm should have 400mm lap.

 

[Phil_D]

Again, thanks everyone for the input

SBR mixed with pure cement & rollered on. To seal & create waterproof bonding layer.

Then a few bags of self leveling compound to smooth off.

Dry, scour then paint with epoxy.

This seems to be the route that I’m going to try. Is all SBR the same stuff? Screwfix sell the cementone stuff for £23/5L.

Does this go on easily enough when brushing rollering on? Or does it need to be physically levelled out somehow as you apply it?

Any advice on the best way to mix?

 

[ukracer]

I've got this on a floor, lack of cement basically.

I've tried some hardener, complete waste of time and effort. View attachment 189647id go for decent workshop floor paint to consolidate it, failing that pva as suggested.

Don't go for the cheap single pack...mine took 3 months to dry........

 

[Phil_D]

For reference this is what the slab looks like after sweeping my garage out. Exposed aggregates, never ending dust, holes etc. Would be able to dig into it with a screw driver if I tried in certain parts.

Would SBR be capable of significantly improving this? I’m not expecting perfection just want less dust!

 

[brightspark]

Again, thanks everyone for the input



This seems to be the route that I’m going to try. Is all SBR the same stuff? Screwfix sell the cementone stuff for £23/5L.

Does this go on easily enough when brushing rollering on? Or does it need to be physically levelled out somehow as you apply it?

Any advice on the best way to mix?

sbr is a bonding agent diluted with water either brush it in with a soft sweeping brush or a large roller .you can add cement to make a slurry but not 2 much. you can get sovereign but its about 50 quid a gallon or cheaper ones 22 quid ish that's probably as good just not paying for the name if its only to seal give 1st coat 50 -50 mix with water and second coat a bit thicker . it wont build up the surface just seal it

 

[Rig Pig]

Whatever you do don't be tempted by single pack floor paint, it's rubbish no matter what it promises on the tin. I bitterly regret using 'Dimond hard' paint on my floor, it just peels up, but not enough to leave a clean floor to paint with 2 pack

 

[Phil_D]

sbr is a bonding agent diluted with water either brush it in with a soft sweeping brush or a large roller .you can add cement to make a slurry but not 2 much. you can get sovereign but its about 50 quid a gallon or cheaper ones 22 quid ish that's probably as good just not paying for the name if its only to seal give 1st coat 50 -50 mix with water and second coat a bit thicker . it wont build up the surface just seal it

Sweet, sounds easy enough. So I take it mixing in cement is just for patching holes and cracks then? Would there be any reason why I couldn’t just get it sealed with SBR and water for now and then possibly patching some holes with a slurry further down the line?

 

[brightspark]

Sweet, sounds easy enough. So I take it mixing in cement is just for patching holes and cracks then? Would there be any reason why I couldn’t just get it sealed with SBR and water for now and then possibly patching some holes with a slurry further down the line?

just seal it .you can patch the holes and cracks at a later date using more sbr to prime it

 

[Phil_D]

just seal it .you can patch the holes and cracks at a later date using more sbr to prime it

Sounds perfect, just hope the stuff works st least somewhat well.

In true fashion I’ve bought 2x5L of the stuff off eBay for under 25 squid. Garage is 16’3’’ by 14’8’’ - I hope that’s enough to get me at least started!

 

[brightspark]

Sounds perfect, just hope the stuff works st least somewhat well.

In true fashion I’ve bought 2x5L of the stuff off eBay for under 25 squid. Garage is 16’3’’ by 14’8’’ - I hope that’s enough to get me at least started!

will cover it no problem

 

[pandemonium123]

+1 on the cheap 25l poly floor paints.

my last garage had some pitting in the concrete from a shower when new builder never covered it.

rollered on....probably to think TBH, but some of the pitted bits never dried in 4 years & generally discolored terribly.

I have 3 packs of this waiting to go on
https://www.floorsaver.co.uk/collections/paint/products/epoxy-floor-paint-5l

But the floor will be ground flat smooth first.

 

[Phil_D]

Made a start tonight, cleared the worst half and swept it out. Probably got about 5kg dust off it!

Bit disappointing when my SBR arrived, turns out I’d ordered 2x 2.5L rather than 2x5L. The eBay picture was misleading!

Anyway I mixed up 2.5L of SBR with equal parts water and used a soft brush to try and brush it round. It soaked into the floor so quick it was very difficult to get any sort of even coverage (I was just tipping it out a bucked bit by bit).

Was going to put the second 2.5L straight on but decided to let this stuff dry overnight anyway and hopefully the second coat will go on a little easier.

Expectations are still low at this point, but I’m only £24 down so not the end of the world if it doesn’t work

 

[premmington]

Made a start tonight, cleared the worst half and swept it out. Probably got about 5kg dust off it!

Bit disappointing when my SBR arrived, turns out I’d ordered 2x 2.5L rather than 2x5L. The eBay picture was misleading!

Anyway I mixed up 2.5L of SBR with equal parts water and used a soft brush to try and brush it round. It soaked into the floor so quick it was very difficult to get any sort of even coverage (I was just tipping it out a bucked bit by bit).

Was going to put the second 2.5L straight on but decided to let this stuff dry overnight anyway and hopefully the second coat will go on a little easier.

Expectations are still low at this point, but I’m only £24 down so not the end of the world if it doesn’t work

From the pics - the floor is so "pitted" - you are gonna end up "self levelling it" to get any finish at all...

 

[brightspark]

wont be level but it will well harden the surface. so will cover easily. second coat will not soak in hardly

 

[Phil_D]

From the pics - the floor is so "pitted" - you are gonna end up "self levelling it" to get any finish at all...

wont be level but it will well harden the surface. so will cover easily. second coat will not soak in hardly

Not going to level at the moment, I’m actually going to be converting at least half of it into a home gym so will be laying down some 18mm thick rubber horse stall mats. Just want a dust free top to put them on

 

[pandemonium123]

Might as well level it now while the sbr bond is clean and ready to go.
If you put the mats down, it will all need cleaned & done again.