Damp Patches on Entire Wall

baser999

We had damp patches to either side of front bay, about 4 foot from skirting. Builder said that being a 1900-ish property, with no obvious cracks outside, this could well be down to damp brickwork. He broke plaster away inside and re-plastered and suggested that we needed to paint outside with decent masonry paint followed by a waterproofing solution. Managed to get this done over a couple of dry afternoons in November and no issues since.

Ben1989

Thanks Baser.

But how do the bricks get damp? And what's stopping them getting damp again? We skimmed over old plaster (not sure if it was original or not) and the plaster seemed to just not dry. Not sure how re-plastering would change anything?

stuart45

Brick walls can hold a lot of moisture, and take a long time to dry out, especially if the moisture can't escape easily. Some types of brick hold a lot more moisture than others.

Ben1989

Thanks Stuart. But where does this moisture come from if it's 'sealed' both sides?

stuart45

If the external wall is sand/cement render there will always be minute cracks somewhere that allow moisture in. Inside, a certain amount of condensation will find it's way into the wall. It's difficult to completely seal a wall on both sides, as buildings are always moving. Some moisture can also come from the top of the wall as well.
With a solid wall like yours, in theory all the mortar joints are full, but in practice, the inside joints are only partly filled, and this allows water to sit in there, and also travel around the wall.

FreeBear

stuart45 said: With a solid wall like yours, in theory all the mortar joints are full, but in practice, the inside joints are only partly filled, and this allows water to sit in there, and also travel around the wall.

For a long while, had problems with water dripping from the middle of my kitchen ceiling - An extension put up in the mid 70s. The leak would only occur when it rained really hard. Messed around patching the flat roof, adding flashing, etc. Nothing really helped. A roofer pointed out a crack in the render (solid 9" brick wall) some 1.2m away from the kitchen extension. That has now been repaired, and have yet to see any further leaks inside.

Water can indeed travel inside a wall. In my case, over 2m from the source.

Ben1989

So I'm wondering what the course of action is? I think I filled in all the gaps in the render, what next? Hack off all the plaster?

Ben1989

Any suggestions peeps?

markin

Run a dehumidifier, and did you get a rad in there yet?

Is the piv set to max?

Ben1989

Yes PIV set to max