1950's Semi Rebuild -SE London

[donj]

Just saying Hello,

 

We are rebuilding a 1950's semi. For my sins I am the owners "retired" father and thus have been bought in as the unpaid gofer, info gatherer and fixer...  

 

Project summary:

 

This a big restoration job on a 1950's built house. Plan is to add kitchen extension and loft extension and rework interior. Project includes adding 100mm exterior insulation to first floor and re-rendered outside walls, adding ~30mm interior insulation to outside ground floor walls and re-plaster. Digging out ground-floor floors, adding insulation, fitting under floor heating and re-screeding throughout. Lifting first-floor floor boards, insulating and fitting underfloor heating throughout first floor and loft extension. Replacing all windows and doors with either double or triple glazing. Insulating roof spaces to 250mm equivalent. Fitting MVHR system and an air source heat pump for heating and DHW. Rewiring will include new lighting, new rings, data cabling for a distributed network, distributed TV and sound  Then new kitchen, 2 bath/shower rooms and loads of built-in furniture.  

 

Objective is a long term, efficient comfortable home.

 

Current status is that we are ready to pour ground floor have most interior demolition complete and have the first floor and Loft extension ready for first fix.

 

Going to be very busy.

 

DonJ

[Mr Punter]

Hello and welcome.

 

You have a fair amount of work there.

 

You may find there is not a huge benefit in installing UFH on the first floor and loft.  The heat will tend to find its way up anyway.

 

Have you calculated your heat losses?

[alfaTom]

Welcome!
Your proposal sounds very similar to what we are trying to achieve, although we weren't planning on EWI.
As Mr Punter suggests, do a heat loss calculation. I have it in plans to UFH & insulate on first floor but once I have done some calcs it may not be needed. I am leaning towards overengineering at this point though.

Curious to know what your MVHR proposals are; will you be dropping ceilings or boxing the vent runs in?
As you are looking at 30mm interior ground and 100mm exterior upper have you thought about airtightness tests? 1950s + MVHR will need a fair bit of gap-plugging I imagine to be effective...