Best render for blown bricks

[pilgrim]

Hello, I have quite a lot of frost damaged / Blown bricks below the damp proof level on the outside of my house, I am hoping to just render up to the damp proof level to protect the wall. I was wondering if anyone has some advice they can share on the best process / type of rendering product for doing this with?

It is a semi detached house with an extension going on the rear and a porch on the front so not many meters of rendering required luckily, this side wall will have my heat pump against it and will not be seen very much so the aesthetics are not a priority!

Thanks

[twice round the block]

Someone never used frostproof bricks below the dpc all the way down to the footings then.

In normal circumstances all the brick work would be cut out in sections and replaced with  frostproof bricks down to the footings. Bit like Underpinning.

 

Is your chimney stack or neighbouring houses in the same condition?

 

As for render your just pretending the problem has gone away.

 

Your concrete path / drive should not butt upto the house  there should be a minimum gap of 100mm filled with pea shingle.

[pilgrim]

1 hour ago, twice round the block said:

Someone never used frostproof bricks below the dpc all the way down to the footings then.

In normal circumstances all the brick work would be cut out in sections and replaced with  frostproof bricks down to the footings. Bit like Underpinning.

 

Is your chimney stack or neighbouring houses in the same condition?

 

As for render your just pretending the problem has gone away.

 

Your concrete path / drive should not butt upto the house  there should be a minimum gap of 100mm filled with pea shingle.

 

Neighbours house is not as bad, but does have some frost damage. my neighbours are not sure what was done to their house but it looks like it's been painted below the dpc.

Chimney stack is fine, no signs of frost damage, it's built with a different type of brick.

The inside skin of the house is harder engineering bricks

This is a 1930s semi all the others in the street use a darker red brick not the softer orange brick used on this pair.

Part of the problem with my half is that it was left abandoned for 25 years and was over grown with vegetation which would have trapped the moisture against the wall.

 

I can cut the concrete path back 100mm that's not a problem.

[pilgrim]

Heres another picture where I have excavated down to the footings. weirdly you can see that they had tougher bricks on the footings then switched to softer bricks 2 courses below the DPC, the course of bricks below ground level havent blown jut the ones above ground that have been eaten by the frost.

Any good ideas for the best way for me to fix this?

[Mr Punter]

Once you cut back the path and either fill with shingle or have a channel drain the wall should dry out.  I would be wary of doing any rendering until it is bone dry for at least 6 months.

[pilgrim]

Thanks @Mr Punter how deep do you think I should dig the drain channel? 

[Mr Punter]

150mm deep should be good.  Cut the path back neatly with a grinder.  Fill the channel with shingle or use an Aco type drain.

[pilgrim]

thank you @Mr Punter i'll get onto this soon before it gets much wetter!

[twice round the block]

You'll have to be careful not to bridge the dpc with any render stop you use and try and put 30° angle finish on it.

Sand and cement render will be stronger than a porous face brick at the end of the day.