Garage Floor Damp Issue... Any suggestions please?

[Richard77]

I'm looking at doing this as cheap as possible with as little disruption as possible. It's only going to be a plant room, with occasional gym use.

If it is only going to be a plant room/gym where is the problem with raising the floor level?

I still want it to look like a garage from the front.... The floor at the front would then be at least 150mm higher than the ground.

Would look... Odd. A step or very steep ramp?

[jonc_uk]

I'm just after a quick, easy, not completely botch-job (semi-botch is ok).

Ok.

1. Wait until the blocks and floor are dry.
2. Apply a thick layer of bitumen paint with fibres in it (used for roof repairs) on the inside, up to the DPC and lap over on to the floor slab as a primer.
3. Apply a layer of flashband which runs from the bitumen on the floor slab up the blocks. Eg. 4 inches on the floor, min. 4 inches up the blocks. Use a roller to make sure it is properly stuck to the bitumen.
4. Now pour the liquid dpc to cover to the edge of the floor.

And don't put any fixings through it when you do the walls (eg. foam-fix it). And keep a gap between the PIR insulation on the walls and the floor.

[spread-tee]

A fillet basically, just a triangular strip of sand and cement applied along that bottom edge, bring it say 5cm up and 3cm out from the wall, a couple of buckets of muck and your done. Clean up the area first with a good scrub, prime with SBR or similar, then mix up your mortar say 4 sharp sand to one of cement, and add a bit of SBR to the water, keep the mix on the dry side and trowel it in. After a couple of hours you can fettle it to get nice straight edges, then after a few days paint the outside of the first course and the fillet with the blackjack.

It won't last for ever but it costs very little takes a few hours and if needed can be done again in 5 years time..........no worries.

Desp

[Richard77]

Thanks for the suggestions Desp and jonc_uk.... Much appreciated.

[AGT]

Sika do a water proofing agent in a 5 litre can you pour it down cracks to help seal, they also do other additives that added to cement make it waterproof, so making a runny slurry can help.

We have a bit of success in areas we cannot access.
Worth a google

[AGT]

Sika also do a liquid damp proof membrane, I’ve used that successfully in a 100 year old slab that we wanted to put a carpet down in( retail space)

Maybe an aco drain at the front/french drain around the perimeter too

[Richard77]

Thanks AGT... I'll give them a Google. Cheers

[Richard77]

Finally got round to doing a bit today....

Took the edging blocks/bricks (paviors?) up to try to expose the footings.

Right side (single skin block)... Moved sand and soil away from footings:






Left side (single skin block)... Moved the stones away from footings:




Rear (double skin brick)... Sand and soil to bricks, didn't go down to footings:






I'm edging towards either sbr/cement slurry or a few tins of black jack on the floor inside up to the damp course on walls.

Prime the floor and lash a load of self levelling compound down and pray to the Gods of Umidus!

Then tackle the outside at a later date for a more permanent solution.

[spread-tee]

That last piccy you posted, is that the first course of block on the slab? the bed joint looks a little iffy wherever it is, I would rake that out and point up again with a little waterproofer in the mix. Then now you have exposed thew outside concentrate your energies there and stop the damp before it gets into the blockwork. The inside will dry soon enough and may not need any further treatment, although if you feel it appropriate it wouldn't do any harm.

Desp

[Richard77]

That last piccy you posted, is that the first course of block on the slab? the bed joint looks a little iffy wherever it is, I would rake that out and point up again with a little waterproofer in the mix. Then now you have exposed thew outside concentrate your energies there and stop the damp before it gets into the blockwork. The inside will dry soon enough and may not need any further treatment, although if you feel it appropriate it wouldn't do any harm.

Desp

The last pic is the corner of the original double brick wall that was there that just separated the garden to the drive. I stupidly told the brickie to use that as the rear wall rather than knock it down as it was solid and was in the correct place.



The inside is dry to the touch already. It's only a bit of water that seeps through when it rains heavily.