Ready to hire?

Post your job in minutes, browse real reviews and choose who to speak to.Post a job

Need some tips or advice?

Extensions

Extension to house with external insulation - best way to tie back to existing structure?

Anonymous user 09/03/2024 - 3.11 PM

Hi all, Looking to build an extension to the rear of an existing terraced house that has had external wall insulation installed retrospectively. Has anyone ever done something similar? My concern is that the timber frame won't be able to be fixed back to the structure, and that the roof flashing may not be able to be wraggled into the foam insulation. I'm thinking that we may need to cut the extension profile out of the insulation to effectively 'slot' it in against the existing house, but wonder if there is a better way to do this. Appreciate a structural engineer may be able to advise on this a bit better, but hoping others have some advice to share. I had intended on contacting the insulation company to see what they advised but they've since gone bust so can't do that. Cheers. EDIT: picture of the house can be seen here; https://www.dropbox.com/sh/9m7yi6wugj9frgd/AACewtvzifYZaT4LsYf4vPlPa?dl=0

Are you a tradesperson and able to answer this question?

4 Answers

Cripps Construct Ltd

Rating: 5 out of 5

Fareham

Morning Stuart, Could you provide any photos or drawings of what you have? I may be able to help and can put you in touch with a SE if you need a good local one.

Answered18 July 2020

Anonymous user

Hi You will need to strip back the cladding and insulation and see what the sub frame is I.e. wood or steel then the SE would advise a tie in solution and maybe expansion joint. There will be a solution.

Answered19 July 2020

Bob Fice Builder

Rating: 5 out of 5

Plymouth

Hi Stuart. Ref. Exterior insulation. I would take off insulation to the shape of extension as photo. That way you can get lead soakers to roof where they need to be. Also by taking insulation away you are maximising space plus you will get good" tying in "to house. Good luck with the project.

Answered1 August 2020

Light Space Build Limited

Rating: 5 out of 5

West Byfleet

As you already identified the extension needs to tie in to the existing masonry, not the insulation. Hopefully the builder will be able to neatly cut the insulation to fit the new walls into but where the roof is you might need to cut the insulation away a little higher to fit the flashing behind it into the masonry wall and then fit back some insulation with a drip bead on the lower edge. Prepare yourself for a little rework on the insulated wall and finish with render. It will be easiest to fix if you can identify which render product was installed so the new and old match as closely as possible although unless you re-render the whole wall it is not going to be an invisible repair.

Answered16 August 2020