Advice for damp wall drainage

[mikiexz]

I posted many years ago about this problem.. might have been 10yrs!!!, I never really got around to fixing it. But as now I am re-plastering / decorating inside, I really need to sort it out.

The house is 1927, solid wall construction.

My drive in block paved (by the previous owner) and slopes down towards the house, there is no drainage. In very heavy rain water can sometimes pool against the house in a couple of places. This is not helped by being on a slight hill, my neighbours drive which is flatter and 1ft above can also contribute to the water.

The DPC, I’m not sure of its location although in some places a chemical injection has been done in the past (again previous owners). The joist sit on the same level as the air brick, the floor is about halfway up the air brick. That’s a little strange because half the air brick backs on to the skirting board.

The wall inside seems to have damp above floor level, but not all the way along. The skirting board seems to have helped spread the damp. The wall has sand and cement up 1 meter, obviously from when chemical DPC has been done. Only small part of the edge of the floorboards had minor rot, one of the joist ends looks to be getting a bit soft.

I removed some of the pavers next to the house, the first course of mortar below this appears to be mostly mud. The next course lower seemed to be in better condition in the one spot I dug down so I have left that. Today I removed a lot of mud from the joints and filled that with mortar, 4:1 mix pushed right in.

So my plan is to put in a CD422 clark drains around the front and side of the house, put this where the soldier course is now against the pavers (to avoid where the gas/electric connections that come up against the house. This will leave 58mm gap from the wall, to fill this I would cut the old pavers down to that size (hiring a block cutter).

My question is, does this sound like it will solve my problems, is it a good plan?

Here are some photos
https://photos.google.com/share....2Q0aVRB

[seanandruby]

i take it you have read this page ?

[mikiexz]

Hi Sean, thanks for replying.
I have read the page, although I am none the wiser to where my DPC is. Might it be only the two courses of what I assume are engineering blocks? They are not as blue as modern ones, more of a mix of red and blue. From looking up and down my street my ground level looks to be similar to everyone else. The bottom of the air bricks sit more or less on the ground. Some houses have the air brick slightly higher up the wall on one side because of the slope of the road. The more I think about it the less I think I need to lower any ground. :0

[Tony McC]

I'd be inclined to install a linear channel drain (and the CD422 is better than many) tight against the house with its top at least 6mm below the base of the air-bricks.
Where you have utilities going into the house, these can be cut-in to the linear channel and sealed with thiosulphite or other suitable waterproofing mastic.

This channel would not only collect excess surface water, it would provide a dry channel to enable the bwk to breathe and thereby help alleviate the ongoing damp problems.

[mikiexz]

Thanks for the suggestion Tony. Now looking at the channel specs there is a few cm so at least of the electricity I might not need to cut into the internal channel. The gas pipe would intersect more with the channel I think, but if as you say sealing with a mastic would work I will do that.

Is there any problem with concrete the drain sits on being right up against the house? or should there be anything between the bricks and that?

[seanandruby]

..
Or a good quality elastomeric sealant :;):

[Tony McC]

There's no great need to seal between channel and masonry, but I know some installers like to do so. It can't really do any harm but I always feel its a abit OTT.

[mikiexz]

Thank you for the help, I'm close to finishing now. I spent most of my time not on the drainage but re-pointing and replacing bricks below the surface.

This is what it looks like now
https://photos.app.goo.gl/6DCrovQd2CGBGRhs9

Ok its not an amazing job, but functional and looks ok from a distance!

Now my only concern is what should I do with any small gaps between paving and the drain. Probably I should have put the non cut flat side of the block towards the side of drain!

Is it worth putting some resin mortar / sand or some other joint in the gaps between the paving and drain?

[seanandruby]

Yes do a mortar joint otherwise you will keep getting sand loss between other blocks and will look neater.

[mikiexz]

Yes do a mortar joint otherwise you will keep getting sand loss between other blocks and will look neater.

Thanks Sean I will do and thanks to Tony and everyone else that helps out here. It's such a great resource.