Insulating a 1967 timber framed bungalow

[esalglop1945]

Hello Budding Builders. I have recently bought a 1967 bungalow with 20* pitched roof in a rural location close to my home in Cornwall. It was inhabited by the builder and his family until he died last year with no alterations. Mainly brick facing, airgap, studs, timber cladding, airgap, plasterboard. Floor Concrete battens Chipboard. The loft, internal walls and external soffits display a myriad of cables, wiring, phone, Tv, security systems. I hope to raise the bungalow to close to Passivhaus standard. There is currently no sign of damp in the property. 

Prime question. Can I leave all external walls and plasterboard intact, erect a touching super-insulated studwork including all plumbing and electrics first fix?  

[Russell griffiths]

Why leave the plasterboard up, rip it all out to expose all the studwork, you will need to satisfy yourself that is sound first before you cover it up with extra stud walls. 

Then make a plan, I would probably build a stud wall internally like you say and insulate both walls. Then air barrier, batten for services and then re board. 

[Onoff]

43 minutes ago, esalglop1945 said:

to raise the bungalow to

 

...the ground.

 

Best bet! ?

[Andehh]

We started off on this journey & ended up demolishing! Would have saved a decent chunk had we started off with that plan in the first place!! 

 

 

[esalglop1945]

When did you do this? The cost of demolition is surely now serious. A new sheet of plasterboard is £8.50, but costs £12 to dump. Would you really destroy this building?

[Andehh]

Depends on the situation, ours was a timberframe '70s with zero insulation except attic & 3 extensions over the years. It was the wrong way round for the garden, so we were needing to remove 75% internal timber walls 

 

We were going for a full refurb & reroof, and significant 130sqm extension. The refurb raised several concerns eith people in terms of what they might find. 

 

Overall project was around £500k refurb vs £540k rebuild (vat removed off rebuild), which made it a no brainer for us! 

 

Demolition was only around £15k IIRC. 

 

Edited January 15, 2022 by Andehh

[Soulfish]

I'm in the middle of a massive refurb of a 1970's bungalow. We've only kept the external walls and roof (and even that has had extensive repairs); all window/door positions and the slab have been relaid. Due to changing what we'd be doing (keeping and living in it vs selling) part way through we'd  initially decided not to demolish and rebuild but now really wish we had done - would have been a lot quicker and would have solved a lot of our niggly annoyances with things we didn't resolve!

[Gone West]

1 hour ago, esalglop1945 said:

Would you really destroy this building?

I wouldn't and I've done renovations and a new build.

[Iceverge]

What a nice project.

 

I'm optimistic about keeping it for 3 reasons. 

 

1. It's pretty and appears to be well kept.

2. It was never altered meaning it must function well and also doesn't suffer from conflicting build methods of different eras. 

3. The builder was unlikely to make a hash of their own house. 

 

Might you perhaps be able to sketch a cut through of the wall please with dimensions. 

[esalglop1945]

On 15/01/2022 at 11:15, Russell griffiths said:

Why leave the plasterboard up, rip it all out to expose all the studwork, you will need to satisfy yourself that is sound first before you cover it up with extra stud walls. 

Then make a plan, I would probably build a stud wall internally like you say and insulate both walls. Then air barrier, batten for services and then re board. 

 

14 hours ago, Iceverge said:

What a nice project.

 

I'm optimistic about keeping it for 3 reasons. 

 

1. It's pretty and appears to be well kept.

2. It was never altered meaning it must function well and also doesn't suffer from conflicting build methods of different eras. 

3. The builder was unlikely to make a hash of their own house. 

 

Might you perhaps be able to sketch a cut through of the wall please with dimensions. 

 

22 hours ago, Andehh said:

Depends on the situation, ours was a timberframe '70s with zero insulation except attic & 3 extensions over the years. It was the wrong way round for the garden, so we were needing to remove 75% internal timber walls 

 

We were going for a full refurb & reroof, and significant 130sqm extension. The refurb raised several concerns eith people in terms of what they might find. 

 

Overall project was around £500k refurb vs £540k rebuild (vat removed off rebuild), which made it a no brainer for us! 

 

Demolition was only around £15k IIRC. 

 

I am 76 years old. I do not have any private pension, saved money for this final project. I have a budget of £110k.

[esalglop1945]

14 hours ago, Iceverge said:

What a nice project.

 

I'm optimistic about keeping it for 3 reasons. 

 

1. It's pretty and appears to be well kept.

2. It was never altered meaning it must function well and also doesn't suffer from conflicting build methods of different eras. 

3. The builder was unlikely to make a hash of their own house. 

 

Might you perhaps be able to sketch a cut through of the wall please with dimensions. 

 

1 minute ago, esalglop1945 said:

 

 

I am 76 years old. I do not have any private pension, saved money for this final project. I have a budget of £110k.

 

On 15/01/2022 at 11:15, Russell griffiths said:

Why leave the plasterboard up, rip it all out to expose all the studwork, you will need to satisfy yourself that is sound first before you cover it up with extra stud walls. 

Then make a plan, I would probably build a stud wall internally like you say and insulate both walls. Then air barrier, batten for services and then re board. 

 

On 15/01/2022 at 11:15, Russell griffiths said:

Why leave the plasterboard up, rip it all out to expose all the studwork, you will need to satisfy yourself that is sound first before you cover it up with extra stud walls. 

Then make a plan, I would probably build a stud wall internally like you say and insulate both walls. Then air barrier, batten for services and then re board. 

Thanks for that advice! I have an endoscope. I will have a peer inside the cavities. I am minded that if it has lasted 55 years with no internal damp signs then leave it be! 

[esalglop1945]

14 hours ago, Iceverge said:

What a nice project.

 

I'm optimistic about keeping it for 3 reasons. 

 

1. It's pretty and appears to be well kept.

2. It was never altered meaning it must function well and also doesn't suffer from conflicting build methods of different eras. 

3. The builder was unlikely to make a hash of their own house. 

 

Might you perhaps be able to sketch a cut through of the wall please with dimensions. 

Thank you for those positive comments. I will explore the walls on Monday and post a sketch photo. 9/10th of walls are brick clad. 1/10 is timberclad as shown in photo. My previous knowledge is from renovating random rubble old Cornish buildings. 

[CharlieKLP]

I like your house too, looks like a nice spot. I wouldn’t demolish it.

 

Are your ceilings vaulted?

 

Agree with what people are saying here but there’s a few things you might be able to do, it depends on how much disruption you want to live with. Not sure how big the rooms are, could you live with dry lining ~50mm. Because you could just skin the walls and spend the rest of the money on new windows.
 

Are you sure you don’t want to replace the weatherboarding, because I’d take that off and put a bit of quilting in there while I’m at it. You can’t do it to the brick, but I’m sure you would appreciate not having to maintain timber in future, I think that would make it look brand new too. 

[SteamyTea]

I prefer the idea of renovation and improvement. I don't think the VAT savings are worth all the other hassle for a reasonably good building.

 

How close to the beach is it?

[Andehh]

Apologies OP, I wasn't being funny bringing up the cost of our project, I just wanted to demonstrate the cost differences we faced in a refurb v rebuild on a similar age/style bungalow to you. FWIW, our project started significantly smaller until my wife & I went through 2 years of multiple bereavements. It's been a very bitter sweet project indeed.

 

We are around £2000psqm for our rebuild (build only/high spec) . Demolition was very quick & easy actually. 

Edited January 16, 2022 by Andehh

[Mr Punter]

On 15/01/2022 at 11:09, esalglop1945 said:

I hope to raise the bungalow to close to Passivhaus standard

 

I doubt you will get anywhere near with your budget but you could certainly make some big improvements.  The floors will be a challenge as you will be looking at around 200mm insulation, so if they are concrete they will have to come up.

 

If you do internal wall insulation you could be looking at losing 150mm from each outside wall.  If that does not work for you you could look at external wall insulation.  You would lose the brick finish but the internals would be unaltered.  It looks like you have a decent eaves overhang.

 

Hopefully there is enough room in the loft for sufficient mineral wool.

 

The windows look OK and you may decide to keep them.

 

You will probably need to redo the flat roof with a proper warm roof.

[Russell griffiths]

If your 76 years old I would put 10 grand aside to cover your gas bill and spend the rest of your money going on holiday, sod the insulation. 
 

[esalglop1945]

The timber frame is as follows 4” brick 1” airgap and plastic membrane, 1” solid diagonal sheathing, 4” airgap, 1/2” plasterboard.

I am hoping that the 4” airgap can be foamfilled even better if it can be achieved by Grant. The property qualifies as it is already EPC E and has Night Store Heaters.

 

[Marvin]

4 minutes ago, esalglop1945 said:

The timber frame is as follows 4” brick 1” airgap and plastic membrane, 1” solid diagonal sheathing, 4” airgap, 1/2” plasterboard.

I am hoping that the 4” airgap can be foamfilled even better if it can be achieved by Grant. The property qualifies as it is already EPC E and has Night Store Heaters.

 

This was our bungalow before we renovated it!

 

[esalglop1945]

On 16/01/2022 at 15:35, SteamyTea said:

I prefer the idea of renovation and improvement. I don't think the VAT savings are worth all the other hassle for a reasonably good building.

 

How close to the beach is it?

The bungalow is 100 metres from Coombe Junction Railway Station. Station was in Guiness book of records as least used but now very populay with 260 passengers annually. Two trains daily take you to Looe, Cornwall for a lot less than the cost of parking AND one of the most beautiful rail journeys in UK. It would have been closed by Beeching but saved by Barbara Castle. Harold Wilson’s parents lived at Station Road LISKEARD.

[esalglop1945]

2 minutes ago, Marvin said:

This was our bungalow before we renovated it!

 

Did you fill the 4” void?

[Marvin]

Just now, esalglop1945 said:

Did you fill the 4” void?

Oh yes and covered it with 50 mm of celotex.

[CharlieKLP]

I really wouldn’t fill the air gap in a timber framed building. You may get condensation and then it will rot.
 

I would advise you to take advice from a timber frame specialist, not just a builder. 

Edited January 20, 2022 by CharlieKLP

[Iceverge]

I've been thinking about this. 

 

I would foam fill the stud bays with a breathable open cell foam like isothane. Importantly don't do the ventilation cavity between the sheathing and the brick.  '

 

I wouldn't put any vapour inboard (I know people will shout at me now!). Doing so would risk trapping moisture within the structure ( because of the plastic membrane outboard).It's only in theory anyway that perfect vapour barriers can be installed. 

 

The isothane will allow the wall to dry to the inside. Importantly, if you have a good installer it will provide a very high level of air sealing, ( this will take a diligent installer and maybe a DIY blower fan on site or else a call-back to fill any holes that were missed. Done well, this will prevent air movement through your walls. This is how almost all moisture gets into structures (not diffusion)  so it a robust way of keeping your walls rot free. I suspect the membrane outboard is imperfect anyway so some drying can take place that direction. 

 

This approach will give an excellent level of airtightness, @Gone West got to PH levels, and good insulation. You will need a mechanical ventilation system of some kind. Maybe some constant volume fans or MVHR if you're enthuastic. 

 

A thin layer of pir under a timber floor will make underfoot comfortable. Pump the roof with 300mm of Cellulose. If you want to have very low heating costs an A2A unit mounted somewhere central will do the trick. If you fancy doing the windows I would say a set of white UPVC 3g with good seals ( pref PH certified) is a reasonable priced option. 

 

There after the gains made by chasing PH levels in a small house are very marginal.

 

My mantra of thermal upgrades. 

1. Airtightness + Mechanical ventilation. 

2. Improving U values. ( including windows and thermal bridges)  

3. Low energy use mechanicals.

4, Renewables. 

 

Good luck! 

 

 

Edited January 22, 2022 by Iceverge

[esalglop1945]

Thank you for all your advice. 
Apparently we qualify for internal insulation, which would be 4” insulation board applied to all external walls and skimmed. I was enthusiastic but the surveyor said that the contractors do not generally do bathrooms and kitchens. As we are converting from a 5 bed to a 3 bed with 2 new bathrooms and a new kitchen then I can completely strip out before they arrive! Haven’t heard back from them. Horrible feeling that it is another Government Initiative that has been acquired by cunning operators entirely for their bottom line, but wait and see!

Actually had another firm say that I qualify this morning?

I know that I need to roof over 3.6 metres between two existing roofs. I actually designed and built a 2 floor garage/Office building some 30 years ago. I was able to get all the calcs from books. I have been visited by two local Architectural Surveyors but very unimpressed. They seem to act like solicitors, that the bill will take preference over liability.

Am I getting too cynical with age!