timber frame of block for extension

[bluebaron]

I am planning a two story 90m2 (45m2 per floor) extension to my 1920's solid wall house.

I am planning to project manage the whole build and was looking at the best route options.

Originally I was going to go Block and Block, render to match existing but was then told about timber frame.

Looking into this i can several advantages and disadvantages.
I plan on an internal open panel frame with block rendered exterior. I have received quotes for approx £25k inc vat for the frame including insulation, roof (untiled), first floor (posi-Joists), and fully erection service.

Obviously from a self build approach this seems very attractive to me. It will save me a lot of time and hassle commissioning just one company to come in and get me watertight in a week!

However I have several concerns mostly however getting the levels right (partially the second floor) and joining to existing (thermal bridging/shrinkage).

When i showed my plans to a structural engineer who loves timer frame for whole build he said it was best to use Block the same as original.

I would rate my skill level as experienced DIYer what would you suggest is the best course here?

Thanks

BB

 

[freddiemercurystwin]

//www.diynot.com/diy/threads/sip-extension.468775/

 

[cjard]

Does your 25k include the external blockwork leaf? If not, then it may be a litt pricey; last timber frame quote I had was for a 3 storey, 280sqm house at 44k erected. Edit: just noticed the inc vat/Sussex parts, which bring it a bit more in line with the mid to late teens I'd have expected for "oop north newbuild"

I don't see a problem with mating the two structures; the blockwork external leaf can b made contiguous, and timber frame attaches to brick/block all the time, so attaching the inner timber to your existing inner brick at the openings isn't really a concern. Not sure why levels would be a problem either; if your old floors are so wonky that eye won't align wi the new ones because they slope, then you'll get at problem regardless of what the extension is made of

 

[bluebaron]

Thanks actual quote was 15k plus £4K erection plus 2.5k to insulate. Plus vat so £26ish. I had another quote for £35k for basically thd same thing. Got two more quotes due in soon.

Hard to guess what 21m block work cost if you include vaulted roof, posi joists, a 6m internal stub wall, insulation and labour but would probably be slightly cheaper overall.