Sealing render and filling gaps

[crizmo]

Hi Guys,
I've been having some issues with damp on some walls in my house. I like in a 1920's semi with no cavity and render over the bricks that has been pebbledashed. I have a channel along the west side of the house. This is the side that gets battered with rain generally.

The channel was full of a lot of dirt and stones so I have now cleared this out. I am also going to fit an extension to one of my downspouts on the front of the house as currently this just goes onto the paved driveway that runs in front of the house and goes right up to the house. I'll channel this water away to the garden for drainage.

I had 3 damp men come out. The first 2 just recommended a DPC after stabbing the meter into the wall on a few walls. The third guy who came out that charged £50 actually looked right round the house and identified the blocked channel at the side of the house, the downspout that goes nowhere on the front of the house and some small cracks in the rendering where damp may be penetrating.

He also pointed out that the bricks that go up to the house and the channel so not seal right onto the bottom bricks of the house as there is a small gap. He recommended dealing these. I've attached some pics as he also said we need to make sure that the channel is fully sealed and water does not leak though it.

Out plastic guttering is all fine and none of the air bricks are blocked. I know we might need a DPC but i'd like to try fixing the little things first and giving it a month or 2 to see if it helps any.

The pics show how the bricks or channel do not sit totally flush to the house. I've crudely drawn where he says it needs sealing. Should I just whack some exterior silicone in these gaps?

Also, I was thinking of coating all of the render on the house in Thompsons one coat Water seal ultra as when the rain batters the house the render just soaks it up like a sponge. Any thoughts on this?

Thanks in advance for any advice offered on these matters.

Cheers

Chris

Untitled

• crizmo
• 15 Nov 2013
• 1

Untitled

• crizmo
• 15 Nov 2013
• 1

Untitled

• crizmo
• 15 Nov 2013
• 1

Untitled

• crizmo
• 15 Nov 2013
• 1

Untitled

• crizmo
• 15 Nov 2013
• 1

Untitled

• crizmo
• 15 Nov 2013
• 1

Untitled

• crizmo
• 15 Nov 2013
• 1

 

[Blagard]

You are not really going to solve anything by bunging silicone into those gaps. They don't look that serious and there is plenty of other opportunities for water to get between bricks with joints that run up to the house.

If it were me I would clean out the gaps as best I can and as deep as possible. Then brush a dry sand and cement mix into the gap. It will set soon after getting damp. It will be more of a tidying job than barrier to water. Use a fine sand if you find building sand is too course.

As for applying sealer to render, it may be beneficial in an exposed situation. But generally I don't favour sealing the shell of old buildings as this can seal in moisture as easily as it stops rain soaking in from the outside. Generally I would prefer to let old solid walls breath.

 

[crizmo]

Thanks Blagard. I've read a few people mention not sealing up old houses. I was under the impression, however, that the Thompsons product allowed the walls to breathe still, while keeping the rain out?

Cheers

Chris

 

[Blagard]

You may well be right about the Thomsons product, I really don't know enough about the product to say if it is good or bad. I have no doubt that it will repell water but how much the wall is allowed to breath afterwards is the question in my mind.

But as I said, in an exposed position it may do more good than harm (if any).

One of the deciding factors to me about using such products would be, does the wall in question give any problems internally, be it either penetrating damp or condensation (A damp wall may get colder and encourage this)? The answer to that would influence if I used such a product or not aside of other solutions such as dry lining the walls internally.

Sorry I can't be more helpful on that. I would suggest that you try and find as much feedback on the product in use before you make a decision.
Cheers