Caversham Passivhaus

[Caversham Passivhaus]

We've taken on the challenge of transforming a charming yet crumbling Victorian terrace house in Caversham into an energy-efficient gem. Our goal is to reach the EnerPHit standard with a Passivhaus retrofit. The house's unmodernised condition offers us the perfect chance to not only perform a comprehensive retrofit, but also rework the layout and expand the property. 

[ToughButterCup]

You might like to have a look at a series of posts by @VIPMan. His project is local to us (Lancaster). We're not all that far up the M6. You might like to PM him. I'm almost sure he'd be pleased to talk to you about his experience - and maybe suggest a visit. The project was superb - I visited a couple of times.

[Dan F]

45 minutes ago, Caversham Passivhaus said:

We've taken on the challenge of transforming a charming yet crumbling Victorian terrace house in Caversham into an energy-efficient gem

 

Welcome!  We're fairly local to you in Finchampstead and recently completed a "passive house plus" new build.  What state of the process are you at, do you already have a builder?  Our guy specializes in passive houses and also does EnerPHit projects.

Edited October 12, 2023 by Dan F

[Iceverge]

Welcome. Always pleasing to see someone doing things properly. 

 

Any more details of the proposed techniques etc? 

[Caversham Passivhaus]

20 hours ago, Dan F said:

 

Welcome!  We're fairly local to you in Finchampstead and recently completed a "passive house plus" new build.  What state of the process are you at, do you already have a builder?  Our guy specializes in passive houses and also does EnerPHit projects.

Hi, It's towards the end of design, close to completing a PHPP assessment that confirms EnerPHit is possible, some enabling works are underway and a restoration of a bay window is now starting. No builder at the moment. I am quite hands on but with no construction background but enjoying the project.

[Caversham Passivhaus]

20 hours ago, ToughButterCup said:

You might like to have a look at a series of posts by @VIPMan. His project is local to us (Lancaster). We're not all that far up the M6. You might like to PM him. I'm almost sure he'd be pleased to talk to you about his experience - and maybe suggest a visit. The project was superb - I visited a couple of times.

thanks. I will take a good look!

[Caversham Passivhaus]

19 hours ago, Iceverge said:

Welcome. Always pleasing to see someone doing things properly. 

 

Any more details of the proposed techniques etc? 

The current work is a restoration to a bath stone bay window. The existing bay window is a UPVC frame with flat roof replacing many years ago the original stonework which was demolished. We are excavating around the existing solid brick base to the corbel foundations and along the way picking out the old stonework which was demolished.

 

The plan is to build aircrete blocks off the existing foundations, using 2.9N/mm2 blocks that have a thermal conductivity of between 0.09 to 0.12W/mK. I am keen on using thin joint mortar as this slightly helps with U-values, but there appears to be a shortage, for example Mannok have an aircrete thin joint system but don't supply the thin joint mortar. Celcon have the block and mortar if you use their blocks. Investigating getting a source from Poland!

 

 

[Mr Punter]

Shevek over on Green Building Forum did an EnerPHit on a Victorian Terrace.  Might be worth looking up if you can make the search thing work.

[Iceverge]

23 hours ago, Caversham Passivhaus said:

The plan is to build aircrete blocks off the existing foundations, using 2.9N/mm2 blocks that have a thermal conductivity of between 0.09 to 0.12W/mK. I am keen on using thin joint mortar as this slightly helps with U-values, but there appears to be a shortage, for example Mannok have an aircrete thin joint system but don't supply the thin joint mortar. Celcon have the block and mortar if you use their blocks. Investigating getting a source from Poland

 

Sounds good. I would encourage a good french drain to keep the foundations dry. 

 

How do you plan to keep the aircrete as dry as possible? It doesn't perform well when wet as I remember. 

[Caversham Passivhaus]

for drainage, planning a backed fill trench with LECA. Realistically I would expect much worse than 0.12W/mK below ground, around 0.20+.

Considering tanking but not sure of that solution at the moment. 

[Iceverge]

Tanking is more robust than a plastic membrane in my opinion. 

 

Will be following with interest. 

[Caversham Passivhaus]

I thought I would update on what I actually did!

 

I eventually managed to find YTong, aircrete thermal blocks that would be suitable with thin layer mortar. The thin layer mortar was additionally difficult to source. Along the way I had settled on the Rawlplug Polyurethane Thin Bed Mortar Foam but I couldn't work with it personally and abandoned the thin layer mortar option.

 

I liked the idea for building the rear extension with that method but it's not going to be the approach I am going to take.

 

For the tanking I decided on Remmers MB 2K Plus to encapsulate the blocks.

 

Additionally I added 200mm of below ground XPS insulation and set out the electric supply alternation.

 

For the backfill I decided to use glass foam aggregate. Partly because the area will be dug up a few times for further utility changes and I am considering using glass foam for the ground floor, so was also trying out the material. It's lightweight but dusty.