Joining "lean to" to exteral insulation

isup

I'm planning to build a shed onto the gable end of my house. the house has external insulation and ill be building the shed to a similar finish as the house.
I'm thinking proper lean to roof and block walls. just looking for advice or if anyone has build against these walls. iI presume ill have to cut into the insulation to fix a wall plate and probably to tie the walls in though i was hoping not to have to .

Gumbo

isup wrote: »

I'm planning to build a shed onto the gable end of my house. the house has external insulation and ill be building the shed to a similar finish as the house.
I'm thinking proper lean to roof and block walls. just looking for advice or if anyone has build against these walls. iI presume ill have to cut into the insulation to fix a wall plate and probably to tie the walls in though i was hoping not to have to .

Has to connect to something solid and structural. May mean cutting into the EWI, so engineer advised.

Calahonda52

It not clear what your plan is for access from the house to the shed and how much of the gable will be covered.

IMO Its a pretty crazy idea to contemplate cutting away the EWI etc.
I would approach it the same was as porches are done on a lot of passive houses, structurally completely standalone and just weather proof the interface but leave the EWI

PROJECT K

ideally avoid it as the detailing is quite tricky even on a new build - you will have to introduce some form of flashing over the new lean to roof and also try and avoid the thermal bridge created by this. Also, in doing this you will damage the existing EWI system and this will need to be professionally repaired.

sky6

I wouldn't cut into the EWI. You could as suggested fit a free standing lean too and then seal it up.
Alternative idea depending on the wall construction is to use chemical anchors or Bolts through the EWI and into the Wall fit the Wall plate to them. then just build from there. Then use Flashband on the Roof to seal the top of the Roof.

chillit

is that flashband stuff any good. I saw a big promo stand of it in some builders providers recently and I wondering how long it would stay on the wall.

Calahonda52

chillit wrote: »

is that flashband stuff any good. I saw a big promo stand of it in some builders providers recently and I wondering how long it would stay on the wall.

Flashband is okay in the right application which this clearly not as the surfaces need to be primed and it is a solvent based primer which may attach the EWI plaster.
There is other stuff, more expensive but works in these cases

sky6

Yes Flashband is great stuff. I used it on a Garage Roof thirty years ago and it's still there working away.
But I'm sure there are similar new products available today equally as good.

isup

thanks all, totally forgot about this thread . you have made my mind up and i think im going for a stand alone structure,. there ive used flashband before and its fairly easy to use.

isup

the whole gable will be covered , just under 30ft. it will be from gable to party wall. there will be a door at the from and rear of the shed/office