Hello! Chalet renovation/build in the French alps

[lenoyeraie]

Hi all,

 

I'm undertaking a project which is sufficiently well outside of my comfort zone & expertise to make it rather exciting. 

 

The building is a 200+ year old chalet on the side of a hill in the Tarantaise valley. The previous owners carried out a large amount of structural work to it (new roof, foundation, concrete floors and walls, door and window openings) but then ran out of steam/funds. It's lain empty for 10+ years waiting for someone foolish enough to take it on. What I'm starting with is an empty shell that retains *some* of the original character (beams in roof, couple of stone walls) but which appears to be structurally sound.

 

I'm currently in the process of finalising room layouts and details for heating and ventilation (MVHR system + heat pump and UFH). It's somewhat a case of building the tracks as the train is bearing down on us, as trades are on-site currently putting up mezzanines and stud walls/etc. 

 

I need to make some decisions on the various components and layouts for duct work in the short term, so will likely be making a few posts hoping for some helpful input. Obligatory photos attached!

[Kelvin]

Looks terrific. Well done for taking it on. Renovations aren’t easy! 
 

 

How airtight is it realistically going to be? Do you have a target figure and a strategy to achieve it? Looks to be a challenge so you probably won’t need MVHR. 

Edited June 3 by Kelvin

[lenoyeraie]

2 minutes ago, Kelvin said:

Looks terrific. Well done for taking it on. Renovations aren’t easy! 
 

 

How airtight is it realistically going to be? Do you have a target figure and a strategy to achieve it? Looks to be a challenge so you probably won’t need MVHR. 

Thanks. Airtightness is indeed a concern, mostly around the interface between the existing roof and stone walls (/internal stud-work). I'm hoping someone may have suggestions on mechanisms to seal between these(!).

 

We'll be installing triple glazing with double/triple seals into the existing (mostly square) openings, which I hope should be more straightforward to airtight. 

 

My main justification for the MVHR is ventilation in the bathrooms at the back of the house (no windows) and the kitchen. The house is at 1,000m altitude, so it does get cold in winter and I'd rather not have standard extractors or a single flow VMC blasting heat outside. Outline floorplans attached for reference.

[Mike]

Loads of potential - would quite like one like that for my next project!

 

1 hour ago, lenoyeraie said:

Airtightness is indeed a concern, mostly around the interface between the existing roof and stone walls (/internal stud-work). I'm hoping someone may have suggestions on mechanisms to seal between these(!).

It can be done, but is best considered alongside the insulation - which will presumably be external, if you're already got trades putting up internal partitions.

 

MVHR certainly a good idea - you don't want trickle vents of open windows in the Alps in winter either. Get a good one with a pre-heater so that it can continue operating fully at low temperatures.

 

 

[Kelvin]

Zehnder do single room MVHR units called the Comfospot 50. 
 

https://zehnder.picturepark.com/service/download/ac23486cb6a946b4bddf3812bbb226a5

[lenoyeraie]

1 hour ago, Mike said:

Loads of potential - would quite like one like that for my next project!

 

It can be done, but is best considered alongside the insulation - which will presumably be external, if you're already got trades putting up internal partitions.

 

MVHR certainly a good idea - you don't want trickle vents of open windows in the Alps in winter either. Get a good one with a pre-heater so that it can continue operating fully at low temperatures.

 

 

We're planning for a mixture of internal and external where possible. We have two original stone walls either side of the building that we'd like to keep exposed, so the plan is to insulate internally on those with PIR between studwork + over the top, vapour barrier + OSB sheathing and externally with 140mm XPS for the remainder. For those internal walls, we'd need to seal adequately between the top of the stud and the underside of the roof/rafters, which I realise may be tricky. I'm also aware that condensation etc becomes an issue, but perhaps that's a discussion for another thread...

 

40 minutes ago, Kelvin said:

Zehnder do single room MVHR units called the Comfospot 50. 
 

https://zehnder.picturepark.com/service/download/ac23486cb6a946b4bddf3812bbb226a5

Many thanks for this - I'd been considering installing a unit like this for the bathroom in the annexe. Given the price however I suspect it could be more cost effective to route everything back to a single larger unit (e.g. I was considering a Zehnder ComfoAir Q350). Helpful food for thought.