Pitched roof next to flat roof Flashing question

[SimonWraight75]

I am having an extension built in the back garden and wanted to ask a question about briding the gap to the neighbours property.

They have a flat roof about 3 m high.
We are having a pitched roof and our front wall will be 2.5m high. Because the tiles need 15 degrees pitch we cannot build any higher. I have tried to show the wall position and roof angle on the photo. How would we cover the gap between the properties to prevent rain getting in ? Do we have to cover this gap ?

Thanks in advance for any advice.

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• SimonWraight75
• 11 Aug 2013
• 1

 

[catlad]

You don't need to cover the gap.

 

[SimonWraight75]

Thanks for the reply Catlad, no gap sounds good to me. I was told that this could cause damp issues and the inspector would ask for the gap to be blocked.

Is this not true ? The gap would be around 50mm - 100mm

 

[CoreMemory]

I think preventing any potential water damage is prudent.

My neighbour's 2 storey house is built right up against mine with no separation. It is having a third story added which will also be built right up against my existing 3rd story and the building inspector requires the virtually non-existent gap to be completely sealed to prevent any water infiltration in order to prevent damage. I also negotiated an agreement with my neighbour who needed a minor variance to build up against my house/zero clearance that requires the same thing and assigns liability to them for any potential water caused damage. To comply, the contractor is going to use a sealant and cover with a sealed flashing or membrane along the length of the adjoining walls.