Roof insulation

[hoyleyboyley]

Knowing a few of you are involved in the building game at various degrees.

Have the normal stuff above the ceilings but have been looking at stuff to put between rafters under the tiles as we have our boiler in the loft, and going by last winter if it gets really cold again the boiler might well come to a grinding halt.

Absolutely no idea what I'm looking for - what do people have / recommend?

[drcarlos]

I insulated my office build with Cellotex. It's 3 inches think on the walls and Ceiling and generally does an excellent job of insulting my 8 x 8 box inside a prefab concrete garage. I couldn't fit 3 inches on the floor so it's about half that and you can feel the difference as the floor is quite cold compared to the rest of the office. My brother used 3 inch Cellotex on the floor of his eco-office and only needs his oil filled rad on when it drops to the minus figures outside. I'd highly recommend Cellotex.

[Jezh]

If you are using the rigid foam insulation such as Celotex / Kingspan / Ecotherm then the correct way to fill the rafters is to leave a 50mm breather space above it. Therefore if you have 150mm rafters you can only install 100mm insulation and so on. To prevent cold bridging you then have to undersail the rafters with a further layer of say 25mm insulation board and tape up all the joints.

Personally if it is just to protect your boiler and you have no plans to expand the loft for additional habitable space I would just construct an insulated box round it with an air vent top and bottom and about 300mm space around the boiler. Its a right PITA cutting all that stuff in between rafters to fit snug especially if the house is old.

[Jobbo]

I agree with Jez. If you start to insulate the loft space rather than above the ceilings, you turn a cold loft into a warm loft and have other considerations to factor in such as the through ventilation, condensation etc.

Have a google of cool loft v warm loft before spending lots of time and money insulating; just keeping the boiler and pipes from freezing is doubtless going to be much easier.

[Gavin]

As Jezh and Jobbo have said, you don't want to build up condensation, build a box!

[Mito Man]

Sounds like it would be easier to build an insulated ventilated box round the boiler mate

[ste]

Why's the boiler struggling anyway? Admittedly I don't know loads about this, but my boiler lives outside. Don't most people's?

[mik]

My name is mik, and my boiler lives in the garage.

(Which is insulated and doesnt get down to freezing)

[dinny_g]

Not sure about the condensation factor but a mate uses Sheep’s Wool as his insulation material

[hoyleyboyley]

Why's the boiler struggling anyway? Admittedly I don't know loads about this, but my boiler lives outside. Don't most people's?

Isn't yours oil or something rural?

Dunno - guy said when he installed it we should insulate in the loft - we obviously haven't, and if we have another really cold winter I'd like to prevent the boiler stopping from working

[Jobbo]

Why's the boiler struggling anyway? Admittedly I don't know loads about this, but my boiler lives outside. Don't most people's?

I’m on oil too - my boiler chap warned me off external boilers but I’d love to put it outside the house. Planning to build a boiler cupboard, fully insulated, as part of our extension.

I’d forgotten how quiet gas boilers were before our holiday this week.

[mik]

Condenser boiler?

In which case the condensate drain pipe can freeze, which backs up, and then your boiler kicks out. Had one in the cellar at out last house and this could be an issue.

The other gubbins should be easy enough to cover via lagging.

[jamcg]

If the boiler is relatively new it should include a frost thermostat which will fire the boiler if the temps get down to 3-5degs. If its an older boiler without this then consider having a frost stat fitted to the system, which should have been fitted att time of install. If it’s a modern condensing boiler and your condensate pipe freezes up then you need to work a solution from the end of the run- it’s rare for condensate to freeze mid pipe, it’s usually the point of termination that freezes first, as you’re in a loft is it just pushed under the roof tiles into the gutter? If it is that’s your problem

[Richard]

My boiler is in the kitchen. It uses gas. I feel this is the new normal.

May I suggest that you buy a nice new house?

[ste]

Yeah it's oil fired Hoyley, no gas anywhere near us.

Why's the boiler struggling anyway? Admittedly I don't know loads about this, but my boiler lives outside. Don't most people's?

I’m on oil too - my boiler chap warned me off external boilers but I’d love to put it outside the house. Planning to build a boiler cupboard, fully insulated, as part of our extension.

I’d forgotten how quiet gas boilers were before our holiday this week.

We have a boiler room (essentially a brick shed / extra bit tacked onto part of the back of the house). Our old boiler was in this. The new boiler specifically had to be fitted outside. Until the building work is completed it's been installed in the old boiler room though. I just took the doors off so that it's 'outside'.

It's like this (library pic, not mine):

[Mito Man]

My parents have something like that, can’t imagine having it indoors as the explosion it makes when it starts up is bloody loud. Love the smell of the exhaust though, especially in summer when the windows cracked open a bit and you get a whiff of it.

[integrale_evo]

Our oil boiler is in the kitchen inside a slightly deeper than standard wall cabinet with no top and bottom, doesn't really seem any louder than most gas boilers to be honest.

[Jobbo]

Ste, it would appear that the main difference between an external and internal oil boiler is that one is in an old filing cabinet and has a fixed exhaust