Building up against an outside wall

[foxglove]

I am going to construct a ramp which will be flaged up to the top of my back door step, then extend the top of the step past the door.
The ramp and flat area will be against the house wall, and also above the house DPC.
I was considering using sub base or similar to get the height, then wack it down.
How do I protect the wall above the DPC to ensure no damp will strike through the house bricks and that will meet building control regs?
Mike

 

[Richard C]

You must either leave a gap above the DPC to allow drainage or insert a vertical DPC; if you bridge above the DPC you will suffer the inevitable consequences.

 

[foxglove]

Richard,
So if I put a vertical Membrane against the wall even though it will be above the DPC it will be ok?

also
How should I attach it to the wall, and how long should I extend it away from the wall at ground level?

Does it matter about covering any vents in the brickwork?

Will sub base not puncture the vertical DPC that I put against the wall?

Sorry for asking a lot of questions but it's all new to me!!!!!

Mikee

 

[Richard C]

Assuming the ramp is for disabled access, you must ensure it complies with relevant Building Regulations Parts M & K; I’m also unsure wheather or not you need planning permission.

So if I put a vertical Membrane against the wall even though it will be above the DPC it will be ok?

Yes but the membrane should extend at least 25mm above the ramp level to allow for running water. Personally I would leave a gap between the ramp & the wall & only bridge across at the very top where you transfer across the entrance threshold; the membrane must extend up & under the door threshold, something like this;
http://www.new-eskimo.co.uk/low_access_seals.html

How should I attach it to the wall, and how long should I extend it away from the wall at ground level?

You only need to temporarily hold it in place; whatever material you build the ramp base out of will permanently hold it in place. As long as the membrane extends vertically below the property DPC you don’t need to extend it away from the wall but it may help to hold it in place while you build the ramp. Extend the membrane well above the final ramp level & cut it off at least 25mm above the ramp when finished.

Does it matter about covering any vents in the brickwork?

Yes it does, you should never cover any air vents.

Will sub base not puncture the vertical DPC that I put against the wall?

No it shouldn’t unless you’re really clumsy with it, plastic membranes are very strong.

 

[foxglove]

Thankyou
That was very helpful.
I will leave a cavity instead of building up against the wall, and knock out a couple of bricks in the walland run pipes out to the outside supportwall {with a grill on, so the vents still do their job.)

Thank's for all the help. It has allowed me to work out the best way to do the job.
Mike