Damp- any alternative to removing driveway?

[Safety First]

Hi all,

Along side of house where concrete drive was laid (before my time), all the floor boards contacting the wall are gone. This was not very obvious at purchase as they are 80% hidden (under stairs and behind kitchen units...those in hallway are fine.

Cause is probably the lovely (and very useful) concrete drive that was laid many years ago right along the side of the house

As sketch, please, what can I do?

I can hire a Stihl cutter and remove a chase then pack void with washed gravel (below DPC level.) I want the air to get down to bricks below the DPC and stop so much bridging...

I know it's not ideal, DPC needs to be 6" above the concrete, but has anyone done anything like this and got some improvements???

Untitled

• Safety First
• 17 Feb 2014
• 1

 

[gregers]

do as you say or instal a french drain.

 

[ree]

Lots of people have done similar and got good results.

Thing is, are your walls cavity walls?

Are the walls rendered, or are you showing a plinth in your detail?

Have you checked for: cavity debris bridging, and cavity insulation?

For the floorboards to rot there must be either moisture coming from the wall or lack of ventilation. You need a plan view of your air brick locations and sizes.

Where are the air bricks now in terms of the raised drive, and where will they be when its lowered?

 

[Safety First]

Lots of people have done similar and got good results.

Good! Thanks Thanks for the input

Thing is, are your walls cavity walls?

Definitely, yes.

Are the walls rendered, or are you showing a plinth in your detail?

Not sure what a plinth is, but the walls are rendered down to the cement drive, or drive went over the render- either/or they are one as far as damp is concerned..

Have you checked for: cavity debris bridging, and cavity insulation?

There has not been cavity insulation put in- thankfully.
At point of re-roofing last month I got bin liners full of nest stuff from birds living in soffits. I pulled out what I could from the cavity. Much of it must have dropped down to the cavity. It seemed to stack up on the wall ties. The cavity is open at the top. I am pretty sure the cavity is bridged at the bottom with nest matter and other building waste, but know of only one way to solve this- remove bricks that offer best access, remove what you can and repeat along the wall. Put back bricks and pack mortar in tight as you do so- Sounds arduous but unavoidable..

For the floorboards to rot there must be either moisture coming from the wall or lack of ventilation. You need a plan view of your air brick locations and sizes.

As my post, the board parallel to the wall has rotted away entirely along the length of the wall *except* for where it was open in the hall. Board under stairs, and board behind kitchen units has gone. This was accelerated due to the covering of the vents

Where are the air bricks now in terms of the raised drive, and where will they be when its lowered?

If the wall is 8m long there is one air brick at 2.5m and one at 5.5m , ish. Both are covered by cement, but show the top 5mm of the vent (galvanized Louvre type things). They are almost useless in this state, I know. I hope to end up with brick vents just above the level of the gravel.

Another comment was to install a french drain. I don't think I am making a french drain here, rather allowing more air and less dense material to bridge over DPC. I have been firmly advised on this site that a french drain is a collecting of water requiring subsequent removal via perf' pipes to an appropriate soakaway. My plan is a lesser option I know but I hope it might help. I don't think I am dealing with volumes of water. Nevertheless some have told me (with approach such as this) that I will create a place for water to pool (?), surely though to pool below DPC and in a quicker-drying medium (large stone chips v's mud/cement) is better..?



Thanks for the encouragement and Q's. I think I will give it a go...

 

[ree]

You can remove bricks for cavity clearance from the inside skin - esp. if the plaster is being re-done. Six bricks out is best size opening, two in the middle, two above and two below.

Cut the render back with the level of the drive surface.

Have you checked/probed the joist tails for rot?
And any damage to skirting board backs?
What about the plaster?

Ideally, you would have four air bricks - one each to be 500mm from each corner.
It might be difficult to get the angle to cut new air bricks in. You might consider "periscope" type vents.
But the old metal vents are useless.


My above plan of vents meant all around the house footprint. Cross and through ventilation is vital.

So long as the drive doesn't slope towards the house the chippings should do the trick.