Variotherm

[Barnboy]

I haven't been given any target to hit for airtightness, the architects details just state "Thermal bridging and air leakage
Building fabric to be constructed using accredited construction
details for limiting thermal bridging and air leakage" 

I didn't know ow anything about airtightness until I'd started.

I've fitted Tyvek Airguard Smart from top to bottom and all around, it's taped to all the windows, any penetrations are taped with their flexi bitumen tape and any corners also have a good dollop of sealer to do the best I can. The only area that hasn't got membrane is on the top of the 1st floor heads of the studwork as that was already up when I discovered I needed to fit a membrane. Here I have the membrane taped up to each side of the heads so any air can only pass through the actual timber if that's possible.

I've not got MVHR, I never knew about this back then either.

We visited the Self build and renovation centre but there were no exhibitors there, only stands to read which I couldn't absorb, that's like reading a book to me, by the time I get to the bottom of the page I've forgotten what was at the top.

Ventilation is from trickle vents on the windows and shuttered extractor fans in the bathrooms and kitchen.

 

 

 

[JohnMo]

I would set the ach rate at 0.2 for now.

 

From the looks of it you will have a ventilation issue. Intermittent fans and trickle vents will not give you enough ventilation with everything sealed up.

 

Upgrade the vent fans to dMEV, these run at a very low rate all the time.   Greenwood CV2GIP are cheap as chips of eBay, Ulta quite, have smart humidity sensing and boost automatically. You need one of these in each wet room. Your trickle vents will end up closed because standard vents are rubbish. So you need to upgrade to humidity sensing or self regulating. 

 

https://brookvent.co.uk/humidity-control/

 

https://renson.net/en-gb/products/ventilation/window-vents

[SteamyTea]

9 hours ago, Nickfromwales said:

Tell sparky boy to just stick to sparking

While taking away his drill, long crosshead screwdriver and Stanley knife.

 

Of all the trades, electricians should understand resistance and insulation best.

[Nickfromwales]

On 30/03/2024 at 09:59, Barnboy said:

I haven't been given any target to hit for airtightness, the architects details just state "Thermal bridging and air leakage
Building fabric to be constructed using accredited construction
details for limiting thermal bridging and air leakage" 

I didn't know ow anything about airtightness until I'd started.

I've fitted Tyvek Airguard Smart from top to bottom and all around, it's taped to all the windows, any penetrations are taped with their flexi bitumen tape and any corners also have a good dollop of sealer to do the best I can. The only area that hasn't got membrane is on the top of the 1st floor heads of the studwork as that was already up when I discovered I needed to fit a membrane. Here I have the membrane taped up to each side of the heads so any air can only pass through the actual timber if that's possible.

I've not got MVHR, I never knew about this back then either.

We visited the Self build and renovation centre but there were no exhibitors there, only stands to read which I couldn't absorb, that's like reading a book to me, by the time I get to the bottom of the page I've forgotten what was at the top.

Ventilation is from trickle vents on the windows and shuttered extractor fans in the bathrooms and kitchen.

 

 

 

Oh dear! You’ve a rather shite architect then. He’s let you spend all that money on AT and then you’re making a cold draughty home to comply with building regs, via trickle and point mechanical extractors. Ffs.

 

What a shambles, sorry to be blunt.

 

Please take some sound advice from us here, and bend over backwards to install MVHR. (PLEASE!!). 
 

Do you have an opportunity and a budget? This would be the best thing you invested in afaic. Really think long and hard before poo-pooing it. 

[Barnboy]

Yes, we thought the architect was good, we'd been given good reviews of him and he was high up in the architects association. His price was simple to understand, as opposed to the other architects who's prices needed a lawyer to understand. 

He didn't like it when I said that I would be doing as much as I can as that was the only way we could afford to do the build, he told me that I could probably do the plasterboarding ! He even wanted to leave the original 1st floor joists that were rotting in the walls.

I will look I to MVHR but we're working on a earn it to pay for it basis at the moment, Covid price increases have wiped us out.

I've just had the 1st floor plastered so whether it's even possible to fit now, I don't know. 

[Barnboy]

On 30/03/2024 at 11:54, JohnMo said:

I would set the ach rate at 0.2 for now.

 

From the looks of it you will have a ventilation issue. Intermittent fans and trickle vents will not give you enough ventilation with everything sealed up.

 

Upgrade the vent fans to dMEV, these run at a very low rate all the time.   Greenwood CV2GIP are cheap as chips of eBay, Ulta quite, have smart humidity sensing and boost automatically. You need one of these in each wet room. Your trickle vents will end up closed because standard vents are rubbish. So you need to upgrade to humidity sensing or self regulating. 

 

https://brookvent.co.uk/humidity-control/

 

https://renson.net/en-gb/products/ventilation/window-vents

Changing the AC/H to 0.2 now gives me a total heat loss of 2536 .

[Nickfromwales]

3 hours ago, Barnboy said:

Changing the AC/H to 0.2 now gives me a total heat loss of 2536 .

Will be a nonsense figure if you then go and introduce trickle and mechanical ventilation imo.

 

20 hours ago, Barnboy said:

I've just had the 1st floor plastered so whether it's even possible to fit now, I don't know. 

Can you sacrifice a little bit of plaster and board for a lifetime of heat recovery, fresh air, zero drafts, lower heating bills, requiring a smaller heating system……list goes on.

 

Getting an AT test done FIRST will be paramount, as if you’re off with this, then MVHR will be useless and pointless, plus detrimental. 

 

Previously linked are some very cost effective suggestions for MVHR equipment. Work a budget around those. 

[Barnboy]

What do people get charged on average for an air test ?

I've just been quoted £450 without a certificate ?

Also I've got these https://www.ironmongerydirect.co.uk/product/trimvent-xs16-upvctimber-window-vent-surface-312-x-16mm-white-931161

Trickle vents, I've been searching about and can't find a humidity version that would be a direct replacement, does anyone else know of any hidden somewhere please ?

Thanks 

[JohnMo]

https://www.bpdstore.co.uk/glidevale-energy-saver-humidity-sensitive-trickle-ventilator/p/182

 

Plus the links I added above.

 

Also look in the ventilation section on here, plenty of mentioned ones there also.

 

The other thing to look at is self regulating trickle vents.

 

I paid just £300 with certificate.

[Barnboy]

I had a look at the ones you recommended and searched for others too. 

The ones that I linked to, that are already fitted to my windows are recessed into the frame so I need to find something either the same dimension, or something very similar to cover the recess but also fit int the recess of the head of my window box.