Waterproofing a block wall

Jeffaillon

Hi there,

I am having a problem with water coming through a block wall. I just finished building a shed a couple of weeks ago. 6' solid block walls, painted with a prime sealer and 2 coats of masonry paint inside and out. The back gable wall is facing west, and living by the sea on the west coast, getting lots of wind and rain. I can feel dampness running along the inside wall after few days of rain, and some water accumulating at the bottom of the wall. The 3 other wall are well dry. I am thinking 2 things:
- rendering the wall, which I am pretty sure will solve the problem, but I am useless at it, so I will need to pay someone to do it
- timber cladding the wall with shiplap boards and battens, which I could do myself, but not sure that will suffice to stop heavy rains coming in.

Any suggestion?

michael999999

Give the outside a couple of coats of water and pva.

Or give it a couple of coats of Pliolite paint. Id do the outside first. Then give the inside wall a week or two to dry out and give that a coat of it aswell.

Jeffaillon

Thanks. Am I right to say that PVA is regular wood glue? How much glue would you mix in the water?

michael999999

Jeffaillon wrote: »

Thanks. Am I right to say that PVA is regular wood glue? How much glue would you mix in the water?

Its also used to seal concrete. You can seal up your floors with it aswell.

It'll give the ratio on the back of the tub.

Safehands

michael999999 wrote: »

Its also used to seal concrete. You can seal up your floors with it aswell.

It'll give the ratio on the back of the tub.

Sorry Michael, PVA is absolutely not a waterproofer. Big misconception. Actually, it re-emulsifies (softens) when in constant contact with water.
Use an SBR based paint, which is thick, (600microns) and flexible. Great for this type of application. There are also a number of cement based slurry coats which can be used, rather than rendering.

oisinbutler

Jeffaillon wrote: »

Hi there,

I am having a problem with water coming through a block wall. I just finished building a shed a couple of weeks ago. 6' solid block walls, painted with a prime sealer and 2 coats of masonry paint inside and out. The back gable wall is facing west, and living by the sea on the west coast, getting lots of wind and rain. I can feel dampness running along the inside wall after few days of rain, and some water accumulating at the bottom of the wall. The 3 other wall are well dry. I am thinking 2 things:
- rendering the wall, which I am pretty sure will solve the problem, but I am useless at it, so I will need to pay someone to do it
- timber cladding the wall with shiplap boards and battens, which I could do myself, but not sure that will suffice to stop heavy rains coming in.

Any suggestion?

You're sure the rain is coming through this one wall? Can you post a photo? Its unlikely that the rain would make its way through 2 coats of masonry paint unless it wasn't masonry paint that you used. Is the rain getting in through gaps in the blocks maybe? If the paint is actually seeping through the paint then it will be undermining the paint on the inside of your shed. Look for bubbling or loose paint. Rendering the wall should solve your problem unless the rain is getting somewhere at the roof.

Jeffaillon

Thanks Michael. Got PVA today so might give it a try next time we get a bit of decent weather...

Jeffaillon

oisinbutler wrote: »

You're sure the rain is coming through this one wall? Can you post a photo? Its unlikely that the rain would make its way through 2 coats of masonry paint unless it wasn't masonry paint that you used. Is the rain getting in through gaps in the blocks maybe? If the paint is actually seeping through the paint then it will be undermining the paint on the inside of your shed. Look for bubbling or loose paint. Rendering the wall should solve your problem unless the rain is getting somewhere at the roof.

It is masonry paint for sure. Roof is sound. You can actually feel dampness running down on the inside wall if you're rubbing your hand along. Will try to upload photos tomorrow

whizbang

I just finished building a shed a couple of weeks ago

Its more likely condensation. This wall is the coldest.

Safehands

Jeffaillon wrote: »

Thanks Michael. Got PVA today so might give it a try next time we get a bit of decent weather...

Not a good idea. Great sealer, not a waterproofer. Read the instructions.