Timber Frame Insulation Retrofit

[nnnvvv]

So,

 

We bought a timber frame house (having been told it was masonry!)

 

Looking to find out the best way to retrofit some extra insulation.

 

It appears to be: brick - cavity- tyvek - osb - insulation - membrane - plasterboard.

 

Built around 1995/96.

 

Originally my plan had been to for external insulation + cladding but I guess that's not going to do anything with a ventilated cavity.

 

So given the rooms are a fairly decent size I'm thinking of adding another 100mm or so of rock wool (or similar) on top of the existing timber frame insulation. Perhaps running horizontally studs across the existing vertical studs. We'd remove the existing vapour barrier and fit a new one behind the new plasterboard.

 

Is this something anyone has done before? 

 

Thanks!

 

Nick

 

[Mr Punter]

You may find that improving airtightness will be more beneficial.  What is the floor and roof insulation like?  I am just thinking that ripping out the plasterboard will be a bit disruptive.  If you do end up doing IWI you could use a PIR board which won't eat into the room as much.

[Russell griffiths]

If your set on ripping out the vcl and adding new plasterboard, then I would rip it all out back to the timberframe. 
look at what insulation is there and improve/ remove that, then add more better installed and then insulate over the face of the studs, new vcl and batten and plasterboard. 
 

you could probably do this room by room if you need to live in it. 

[twice round the block]

You could find  more cold rises through the floor if it's block and beam as there won't be any insulation below that in a 90's build.

Photo of 90's built timber frame build.

 

[saveasteading]

I'd leave the pb on, then add pir and a service void. 

As above, get it airtight, and the service void helps with that.

Or there are insulating boards to put on the new inner face.

[nnnvvv]

3 hours ago, Russell griffiths said:

... then insulate over the face of the studs, new vcl and batten and plasterboard. 

 

Not sure I understand insulating over the face of the studs, would that be with some sort of solid block insulation which can be attached to the studs and then the plasterboard hung off that?

[saveasteading]

49 minutes ago, saveasteading said:

there are insulating boards to put on the new inner face.

Pir or eps or fancy fibre stuff. Then pb over it.

[Russell griffiths]

This all really depends on how far you want to go and what you want to spend. 
 

I would do a room by room analysis of all things you want to change

plug sockets, I bet you don’t have enough 

 

then work out your budget and then come back with more questions 

 

if it was me I would rip the plasterboard off, if I’m going to all this trouble I want to know if the frame is in good Nick, has there been any water in the cavity, then I would add more sockets and change the plumbing to how I want it. 
 

then install insulation over the top, vcl and and re board it. 
 

pladter, skirting and then decoration. 

[Russell griffiths]

1 hour ago, nnnvvv said:

 

Not sure I understand insulating over the face of the studs, would that be with some sort of solid block insulation which can be attached to the studs and then the plasterboard hung off that?

Pir board over the studs, all taped together, foamed and sealed around sockets, taped to floor and ceiling 

plasterboard can go directly onto this with long screws, or add a batten and fit plasterboard to that. 
 

or you can use a 50x50 batten and I fill with a rockwool type slab, and plasterboard onto the battens. 
 

lots of ways to skin this cat, 

[nnnvvv]

1 hour ago, Russell griffiths said:

...or you can use a 50x50 batten and I fill with a rockwool type slab, and plasterboard onto the battens.

I think this is the way I'd like to go, ie bring it up to 140mm with Frametherm 32 then vcl then plasterboard. Affixing new vertical battens onto the existing studs would be fairly easy I think (long screws).

 

Thought about going with new horizontal battens fixed to the existing studs to reduce thermal bridging with 2 layers of insulation but I think that might make sheeting more difficult than it needs to be.

Edited February 5 by nnnvvv
Typo

[nnnvvv]

1 hour ago, Russell griffiths said:

... change

plug sockets, I bet you don’t have enough  

I think power requirements have changed since it was built - definitely going to need more than 2 sockets per room.

 

1 hour ago, Russell griffiths said:

 

if it was me I would rip the plasterboard off, if I’m going to all this trouble I want to know if the frame is in good Nick, has there been any water in the cavity

Good point.

Edited February 5 by nnnvvv

[Russell griffiths]

22 minutes ago, nnnvvv said:

I think this is the way I'd like to go, ie bring it up to 140mm with Frametherm 32 then vcl then plasterboard. Affixing new vertical battens onto the existing studs would be fairly easy I think (long screws).

 

Thought about going with new horizontal battens fixed to the existing studs to reduce thermal bridging with 2 layers of insulation but I think that might make sheeting more difficult than it needs to be.

You normally need to think/work backward, so start with plasterboard, and think what way you want to fix it, vertically or horizontally. 
then work back from that. 
 

look up a product called ISOVER it’s an insulation product, they have a fair few YouTube videos on adding extra fluffy type insulation between battens.