Flashing between house and lean-to shed - alternatives

29 Dec 2009
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United Kingdom
Planning on building a lean-to shed along the side of the house, space of about 2m to fence. It's too narrow to get a usable standalone shed and still be able to maintain the walls and fence, so I'm intending going for a lean-to using the wall of the house, maintaining a maintenance gap between shed wall and fence (and also allowing for an overhang and gutter without oversailing the neighbour's garden).

I'm always a bit nervous about doing anything too 'permanent' to the fabric of the building, but as fairly sure the only way to keep this watertight will be to flash between the brickwork of the house and onto the roof of the shed - simply sealing the gap is just inviting trouble. It's a brick-built wall (new-build 2012ish) and between two houses so only exposed to sunlight early morning and fairly well protected from the wind and rain.

Happy to go with the flashing, but thought I'd see if alternatives existed first!

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no use flashing. Flashing is chased into the mortar joint so you are not affecting the fabric of the building as no bricks will be damaged, it can simply be removed and re-pointed
Use lead flashing, cut a track in the brick joints and tighten the lead with another packer piece underneath in the slot you cut. Its the only real option, if you need to remove, just repoint the area. Loads of U-Tube stuff if you need guidance ...........
Just following up on this in case anyone with the same query picks it up later - ended up getting a shed custom-built, lean-to (roof sloping away from the house) with three standard walls and frame-only against the house, so the internal wall of the shed is the facing brick of the house. The builder used a self-adhesive flashing that sticks to the brick without having to channel into the mortar bed. No issues with it over the winter (touch wood). Don't imagine it will last as long as lad flashing, but it's a timber shed - so horses for courses!
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Ironically the awful adhesive gunk left behind by the flashband will leave more of a mess of the wall than the hour or so you would have had to spend repointing.
Seeing as you will be fixing a wall plate to the wall and shelves. The wall will not be pristine if the shed is removed. I have used both lead and flash banding. If the surface is flat (bricks) then flash banding is far the easiest way to go. Mark out the area with chalk and put on two coats of primer. Overlap the length of the flash banding by about an inch either end and it should last more then twenty years. Mine did on a chimney stack.
You could look at a fibreglass roof and buy the fibreglass flashing which also goes in the mortar it will be a lot more costly but done right you won't need to touch it ever again.

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