Timber frame insulation improvement

Scr55

Hi All.

I will be replacing my windows in my house which is timber frame and I have a few questions. The company which installs new windows told me that they use expanding foam for windows installation and they don’t use any airtight tapes, membranes etc. Can you please tell me if it is worth to install some anti-draught solutions for windows in timber frame house? Does it make any sense/difference?

I am also thinking about installing vapour control membrane in my walls when they are replacing windows (I presume it will be easier to do it at this stage). That will require striping plasterboards and applying new insulation (rockwool?) and then that barrier. Do you think it makes any sense?

please let me know if there is anything else I could do improve the insulation (mainly preventing droughts) when replacing windows. External wall insulation (“wrapping”) is not possible in my case because it is a terraced house.

I know that pumping anything into the timber frame wall might cause problems with ventilation.

Thanks for your help!

bfclancy2

https://www.boards.ie/discussion/2058330044/timber-frame-insulation-improvement

yes, when stripping the walls, install new insulation between the studs if required, install vapour/air tightness membrane, and you could put a continuous layer of 50mm PIR over this and then re plasterboard, tape at all the window, this would be a good start

MicktheMan

please let me know if there is anything else I could do improve the insulation (mainly preventing droughts) when replacing windows.

Insulation generally does not address air leakage (aka draughts). Insulation addresses conductive heat loss. Air leakage causes convective heat loss.

Before you go down the expensive route of window / plasterboard / insulation replacement etc, I would advise you to first spend a bit of time finding out a bit more about your tf house and what is (are) the dominant heat loss mechanism(s).

Scr55

Thanks bfclancy2 for yoru reply.

Can you recommend any companies operating in Co. Kildare which will be able to do it?

Can I use kingspan plasterboard with PIR insulation or is it better to put PIR and plasterboard separatley?

kilcul123

Currently undertaking a similar project. What insulation is currently on your walls? My house has 80mm stud with fibreglass insulation (not worth a curse) vapour barrier and plasterboard. I should expect you already have some vapour barrier in place as this would be standard for TF.

We're replacing the fibreglass with PIR, vapour membrane and an insulated plasterboard on top, simply because the 80mm stud isnt enough insulation

As for the windows, I would insist on airtightness tape. It's awkward when installing so the company won't want to do it. Just insist they do or find a company that will.

Scr55

Unfortunately, I don’t know what type of insulation we have. Garden facing walls are 37cm thick and front walls are 32cm. I presume I have to strip one wall to see? I think I will start with a survey (thermal imaging or similar) and then I will follow their advice. However, since house is 20y old I presume that I should be prepared for wall insulation improvements.

Is it very messy to replace wall insulation? Are you getting any company or doing everything yourself? Also, please tell me estimated costs for this project.

kilcul123

Yeah it's a messy job, you'll need to pull out the old plasterboard and start from scratch. My advice would be to do the initial work yourself such as pulling out the plasterboard and old insulation. Quotes will vary but one room (32m²) cost us €1200 for materials and i was able to do most of the work myself but had to get a plasterer in to finish. Depending on your budget you might be best taking it room by room. Gutting the whole house will be messy and expensive. First thing is to see what insulation you have at the moment and see what upgrades are needed.

MrGasDoc

how did you get on? I have a TF home and have gotten a scary quote for internal insulation…. 256m2 done for approx 38k via an SEAI one stop shop. Seems massively more expensive than cavity wall pumping, which we would be doing for a garage/lobby.

I appreciate there is much more labour involved but it seems excessive.

Scr55

Sorry for late reply. I had to postpone my insulation plans as it turned out our bathroom must be done first. However, my plan is to get back to it next year. I don’t know the prices but it seems a lot as for internal wall insulation.

Do you know any reputable companies for internal wall insulation?

Scr55

I

https://www.boards.ie/discussion/comment/121732591#Comment_121732591

I checked what is inside my external wall and I have a few pictures:

From inside it is: plasterboard, some plastic transparent foil, 14cm fiberglass (40cm between studs) and then plywood board I think. I have no idea what's behind this plywood but I will not touch this.

I think I will go with Rockwool/Knauf mineral wool insulation 14cm (0.036 W / (mK)) between studs. Then some vapour control barier + tape and then Kingspan plasterboard with PIR (Kooltherm K16 37.5mm). Mineral wool thickness is 15cm and I have 14cm there but I presume I will be able to squeeze it a bit.

Is is a good setup or would you recommend something else?

Thanks for help!

MicktheMan

I would reiterate my earlier comment about making sure you are focussing on the correct measures to address the real / primary heat loss mechanism before spending 10's of '000's on measures which are both very expensive and disruptive.

The only way to be sure is to have the house tested for the different types of heatloss and make sure an air tightness test is part of this.

MicktheMan

https://www.boards.ie/discussion/comment/122413855#Comment_122413855

IMO, if you go with what you propose are introducing a risk of rot of the timber frame which currently does not exist. Remember, this is a risk which may / may not materialise. However, if it was me, I wouldn't take it.

Scr55

https://www.boards.ie/discussion/comment/122413989#Comment_122413989

Thanks for your reply. I will indeed get a company to check my heat loss/air tightness before I start anything. However, I have done some research on TF insulation and all of them require insulation between studs + vapour control layer under plasterboard. In my case I have some plastic foil instead of VCL and I don't think it is breathable.