function of felt

[jontop]

notaplumber, great news you got it sorted✔
And now its felted it will be much less draughty and cleaner in your loft, and of course......warmer

 

[Nige F]

just make sure you only let a bona fide plumber work in the loft - if a dodgy one pees in the CWS cistern you'll never get rid of the smell now

 

[Brigadier]

Local authorities insist that any building for use as a dwelling must have felt because it increases the energy efficiency of the building.

Local authorities often do not know their arris from the bendy bit of their arm. Taking one of their random demands as proof of correctness is at your own peril / ridicule.......

 

[jontop]

Yep brigadier i know only too well local authorities failings, but they makes the rules
House builders and the authorities that allow, control house building, we are all under pressure to increase energy efficiency (which is a good thing)
The most popular roofing felt brands sell a range of felts, some more insulating than others

 

[Alastairreid]

The most popular roofing felt brands sell a range of felts, some more insulating than others

Roofing felt is not an insulator its designed to prevent water ingress.

Roof spaces should be cold and airy with the insulated aspect at ceiling level.

Even in attic conversions the same applies.

 

[jontop]

Almost everything is an insulator alistair, i know felt is not sold as insulation (unless you specify insulating felt then it is) .
Curtains are not sold as insulation but they definitely keep my living room warmer!
You cant eliminate heat loss you can only slow it, so....
Lets say a house has no felt and the loft is cold, then you add felt and the loft is a little bit warmer , the heat loss from the room below will be a little bit slower

 

[^woody^]

you add felt and the loft is a little bit warmer

I'm intrigued. How much warmer will the loft be?

 

[jontop]

a little bit

 

[jontop]

Every little helps

 

[jontop]

Lots of thin layers (thats what my mum told me) wear a vest under your shirt

 

[freddiemercurystwin]

 

[^woody^]

a little bit

How about qualifying your assertion to help us all in these times?

I'm about to have my cavity walls insulated but if I can make the house a "little bit warmer" by wrapping it in roofing felt, then I'd rather do that.

 

[tony1851]

We all know that the felt is intended to drain any wind-blown rain which may come under the tiles; and we all know that the insulation should be at ceiling level; and that a cold, draughty roof is a healthy roof; and you don't look to council leaflets for the definitive interpretation of Building Regulations etc etc.

But - thinking logically - jontop does have a (small) point. On a cold winter's night, if there is no wind, then technically the house is bound to be 'a bit warmer' due to the felt. Of course the householder would never notice the difference, and it might reduce his heating bill by 1p over a few years, but he still has a point!

 

[freddiemercurystwin]

Yes he may have a small point, in the same way that a roof with tiles on top may be slightly warmer than one without!

But the insinuation that BC require it as a contribution to heat loss is just mad talk.

 

[Grenage]

Still, it probably has more of an impact that the 'insulating tile paint' that used to be sold.

Probably.