External or internal insulation on a house refurb and extension

carrollga

Hi we are about to commence an extension on our 3 bed semi detached house we are also going to refurb and ungrade the house to building regs or above. The new extension two story to the side and back is being well insulated with 200 cavity. However we would like to insulate any part of the old building that isn't being covered by the new build. The problem is that to the front if we externally insulate the old facade there will be a difference in depth between the new and the old. Which mean we either need to externally insulate the new build as well or bring the extersion forward to match the cladding. Its all getting a bit complicated.
The alternative is internal insulation on the old sections which would mean losing room width what would people recommend any advise is greatly appreciated

BryanF

carrollga wrote: »

Hi we are about to commence an extension on our 3 bed semi detached house we are also going to refurb and ungrade the house to building regs or above. The new extension two story to the side and back is being well insulated with 200 cavity. However we would like to insulate any part of the old building that isn't being covered by the new build. The problem is that to the front if we externally insulate the old facade there will be a difference in depth between the new and the old. Which mean we either need to externally insulate the new build as well or bring the extersion forward to match the cladding. Its all getting a bit complicated.
The alternative is internal insulation on the old sections which would mean losing room width what would people recommend any advise is greatly appreciated

i would recommend you externally insulate, what is your architect recommending? its a more comprehensive job if done correctly, it means you don't reduce your floor area or create a situation where the condensation due point is on the interior of the wall.

darragh_haven

externally insulate the old section and the new. it might cost a bit extra but you have it for life. Insulation has no running cost or maintance issues. you might think externally insulating the new section will be over kill just to marry the facades together, but it will be worth it.;)

Carlow52

a 200 cavity wall will be tough to marry into the existing house if u are 'butting new to old' walls

it will also cause problems at wall plate level.

I would EWI the lot and simplify the new wall

air

How would he manage the transition between his house an the neighbours (semi-d) using EWI?

Carlow52

air wrote: »

How would he manage the transition between his house an the neighbours (semi-d) using EWI?

It just stops along the line, very common, whther it looks right etc is sceil eile