How to seal porch against house

[bower1]

I am planning to replace a small wooden porch at the back door. It has a slate roof, and currently has cement fillets against the house. I am trying to decide what will be the best approach when replacing it, as I'm not keen to cut into the stones to put in a lead flashing on the side which slopes, in case the porch will be removed later.

The house is not listed.

Any suggestions?

 

[chuckey]

You do not say if the wall is brick or stone?. If it has a finite life and its against brick, I would used Silicone out of a tube. (Duck). If you wack it on in one thick wodge, it will peel off when the time comes. If the wall is stone with relatively large gaps, use sharp sand with lime. it will chip of when the time comes and any residue can be cleaned of with brick cleaner.
A fancy idea that has just come to me is :- get a piece of plastic (duck) DPC material abot 3" wide and long enough to do the whole height in one go. With brass drawing pins pin it on to the wall side of the wall upright, with its front edge about 1/4" back from the front of the upright. The fun begins, fold the DPC in half with the new bit facing the wall. When you fix the upright against the wall, the DPC will try to straighten and push its self against the wall, hopefully to seal against it.
Sort of like a super sized draught excluder.
Frank

 

[bower1]

The wall of the house is stone with lime mortar. The porch is wood (rotten) and I will replace with wood. Its the roof line between the slates and the stone which I'm not sure about. Most of the other similar ones on the house are a cement fillet. Can this be lime? or will it just crack away.

I've not found silicone works well against lime, unless it is painted (the lime that is), which I don't want to do (its one of the only walls not painted).

Frank, your idea with the DPC may work for the upright, I'll think on that, thanks.

 

[Nemesis]

Check out building regs.

 

[bower1]

I'm considering it a temporary structure and a replacement, so building regs should not apply (the porch is only about 3' by 3')

 

[Nemesis]

Bits of building regs may apply:

Building Regulations approval is needed if the porch has a floor space of more than 30sq m (323sq ft). Most porches are much smaller than this, so are exempt from Building Control if the glazing complies with Part N of the Building Regulations, which means that certain areas within 800mm (2ft 8in) of the floor, and areas around doors, must be safety glazed.


Do I need Building Regulation Approval to construct a porch?

No.

Provided the floor area is 30 m2 or less, the glass within the doors and windows is toughened or laminated safety glass, there is a door between the porch and the rest of the dwelling, and it is not built over a Public Sewer.

 

[Penners]

To flash the joint where your porch roof abutts the wall, you don't have to cut the stonework if you use stepped flashing. You simply cut it into the mortar lines - see the picture below for an example of the technique (look at the angled flashing where the roofline rises at an angle against the chimney brickwork).

Ignore the fact that the flashing in the picture is dressed under the roof tiles - yours would presumably be on top.

 

[Penners]

Building Regulations approval is needed if the porch has a floor space of more than 30sq m (323sq ft).

30 sq m?? That's not a porch, it's a ballroom.

 

[bower1]

Thanks for the info. I'll see whether the staggered leadwork will work with the stone. Its quite wide mortar gaps so it may be ok.