Extractor Fan or Single Room MVHR?

[addjunkie]

You could help that cold spot on the sloping roof, by covering it in insulated plaster board.

 

[Onoff]

Seems you can buy it ready insulated:

https://www.amazon.co.uk/Swiftair-Hydroponics-Flexible-Acoustic-Insulated/dp/B01EJBN3X6?source=ps-sl-shoppingads-lpcontext&ref_=fplfs&psc=1&smid=A3T2WQ6OVSIWHD

I don't though think I need to insulate all the ducts?

- Incoming air duct to the MVHR unit, thinking no. Outside ambient should be similar to the cold roof space.

- Warm, wet extract duct running through loft from MVHR unit to tile vent, yes.

- Warm, wet intake duct from bathroom to MVHR unit, yes as runs through cold roof space.

- Warmed, fresh air duct to the ceiling vent outside the bathroom, yes as runs through cold space.

 

[Pigeon_Droppings2]

As mentioned before...I try to avoid vertical ducts...any condensation could run downwards. Also horizontals should slope downwards to the exit for the same reason.

Sometimes it can't be avoided...in which case keep the vertical as short as possible and insulated well (then cross fingers and toes).

 

[Gareth J]

Don't forget, if you put the box in the unheated loft, you'll need to insulate it too. Otherwise it'll loose a big chunk of any pre-warming. Some come with built in insulation but more is better.

If there's any risk of sweaty bathroom air entering the loft, probably ought to insulate the cold pipes too. Though tucking everything under 12" of rock wool will solve a lot of that.

If going the duct/separate unit route, if there is space anywhere to hang it below the ceiling (airing cupboard?) that will make checking filters easier it will be more likely to get done.

 

[Onoff]

I need to revisit this and get it done. Thinking to lift a line of tiles and remove the old insulation with a garden rake. I just can't get in from the other end where the extension meets the house:

Then reinsulate the loft space to 270mm. I'll also insulate the angled roof bit.

As for an extract fan I was looking at the Airflow iCON but for price!

I was thus mulling this:

Silent Tornado ST100HT Bathroom Extractor Fan + Humidistat Timer | Extractor Fan World

Shop for the Silent Tornado ST100HT Bathroom Extractor Fan + Humidistat Timer. Order online from Extractor Fan World.

www.extractorfanworld.co.uk

Just behind the light, above the bath:

https://flic.kr/p/2pTgvtB

Then with insulated duct out to a vent tile.

https://flic.kr/p/2pUkYR1

Just got one and had my lad 3D print an adaptor:

@brightspark is "uphill" slightly for the duct really that much of a problem? Not sure whether the duct will end up over or under the purlin:

https://flic.kr/p/2pUjiUh

Gable end is a no no as it'd be venting over the patio / barbecue area when someone's taking a ****!

https://flic.kr/p/2pUmrC8

 

[Gareth J]

What made you rule out heat recovery? No appropriate locations?

One of those in wall ones you were considering originally need not go anywhere special, so long as it's acceptable zone wise.

 

[Onoff]

Right or wrong it's in. Can't see it's a sensible thing to just cut the felt but it's what the bloke in the roofing place said to do along with various YouTube videos:

 

[addjunkie]

More insulation too…

 

[Onoff]

More insulation too…

There's a 100mm in there at the mo between rafters. It'll get another 170mm laid perpendicular.

 

[addjunkie]

There's a 100mm in there at the mo between rafters. It'll get another 170mm laid perpendicular.

Did you manage to insulate the sloping part

 

[Onoff]

Did you manage to insulate the sloping part

Only with the 4" stuff:

Need to sort this fascia board out now. Did the one on the gable end a while back.

Trying to find info on a "ventilated fascia board". As I understand it there's a plastic strip thing I can get that will sit atop a wooden fascia. Or maybe a complete plastic one incorporating vents.

 

[addjunkie]

Only with the 4" stuff:

View attachment 512297

Need to sort this fascia board out now. Did the one on the gable end a while back.

View attachment 512298

Trying to find info on a "ventilated fascia board". As I understand it there's a plastic strip thing I can get that will sit atop a wooden fascia. Or maybe a complete plastic one incorporating vents.

The vents nail on the top of the board, but you really need something like this to stop the membrane sitting in the gutter

Eaves Guard Felt Support Tray | Roofing Superstore®

Manufactured from recycled PVC, this 1.5m long rigid roofing Felt Support Tray is a cost-effective solution for protecting exposed roofing felt or underlay ...

www.roofingsuperstore.co.uk

 

[Onoff]

The vents nail on the top of the board, but you really need something like this to stop the membrane sitting in the gutter

Eaves Guard Felt Support Tray | Roofing Superstore®

Manufactured from recycled PVC, this 1.5m long rigid roofing Felt Support Tray is a cost-effective solution for protecting exposed roofing felt or underlay ...

www.roofingsuperstore.co.uk

I've already got some of those. So they sit under the felt?

 

[addjunkie]

The modern membrane deteriorates quickly if in the gutter wet. So the tray or a piece of old style felt stops that

 

[Gareth J]

You've got great access there to consider pouring EPS beads in the cavity. I would, it would make a huge difference to wall temperature in the bathroom and really help reduce condensation and therefore mould risk

 

[Onoff]

I'm going to replace this fascia board with a new bit of timber that I'll treat with preservative:

There was a rotten batten at the bottom but I'm not quite sure how it sat.

Anyone point me at a section of how the fascia board should sit with a batten, facia vent like the one below and tray:

Do I need the bottom batten even if I fit the eaves vent? Does the batten and / or vent provide the necessary kick sometimes effected by wooden kickers as below?

Thanks

 

[addjunkie]

Never seen those vents before, but using common sense…the finished level of vent and fascia should replace whats there now.

Upvc fit and forget. Wood fit and paint and repaint and repaint etc

 

[Onoff]

Never seen those vents before, but using common sense…the finished level of vent and fascia should replace whats there now.

Upvc fit and forget. Wood fit and paint and repaint and repaint etc

Yep, been a bought a length of 150mm black ash effect uPVC fascia. Need to trim down to 4.5" as per the original.

 

[Onoff]

Right or wrong...

There's still a gap under the batten for airflow: