Embarrassingly stupid question on loft insulation

JenniO

Please help - I haven't asked this question till now coz i felt so stupid so do please go easy on me!

My loft floor is boarded out. But the eaves (the actual roof) isn't. In fact between the wood I can see the back sides of the slate tiles that are on my roof.

The question: When talking about loft insulation and heat escaping out of your house through the roof, have I got loft insulation because heat isn't going through the loft flooring I have and therefore the state of the inside roof of my loft is ok? OR have I been living in a house where a lot of my heat / energy has been escaping out of the roof and so therefore I need those strips of pink insulation etc in between the wood on the inside of the roof? God I hope this makes sense! DO I NEED MORE INSULATION OR NOT?

please, any response would be greatly appreciated!!!

jimbo_the_jetset

Hopefully you have insulation under the loft boards (you don't actually say so in your post). If you do then all should be ok.

On another matter you shouldn't be able to see the tiles from the loft. A sarking felt is normally placed down before the tiles (underneath) to act as a second barrier. i.e. if you can see tiles, you have no felt.

cornerstone13

Hi, I don't know anything at all about this, so won't be much help. Sorry.

However, two things - in my loft, between the wood bits, I can see like a membrane/liner thing. Then (from memory, we watched our house being built), they put the V shaped bits of wood up first, covered them in this liner thing, put wooden battens on the outside of the liner and put the roof tiles on to the battens.

Also, could this depend on the age of your house ? If it's very old, maybe they did things differently

When you go into your loft, what is the temperature like? Our loft is boarded and we have lots of insulation between the joists and the floor boards which stops the heat going up into the loft from the house, so at this time of year, it's freezing up there.

Sorry not to be of more help. Can you talk to your neighbours or friends to see what they have ?

WestonDave

The problem with insulating the roof as you suggest is that you will still be heating the loft - which is fine if you use it as living space but if its just storage then its a waste. By the sounds of it your roof will need felting at some stage so that's another reason not to go this route.

Firstly you need to find out what's under the boards. Hopefully it will be full to the top with insulation (looks like yellow cotton wool - but itches like mad if you touch it so wear gloves!). If so then you are sorted.

If there's just a token amount of some scruffy old looking stuff then you haven't got enough and need to put at least 100mm in (recommendations are 270mm but 100mm is normally the amount that will fit if you want to board across the rafters). That means ripping up the boards.

The other alternative that I've seen but not used is something called Spaceboard - which is high density blocks of insulation (possibly polysterene) that you lay on top of the boards and you can then walk on. Personally I'd stick some hardboard over the top to stop it getting damaged as you move things or walk on it but that might be worth a go.

poodlehorse

We don't have felt under our roof either - our house was built early 1900 and we live in Scotland. I believe they didn't felt in those days. Old houses are a nightmare to get insulated as often you struggle getting the insulation in the walls. We have recently taken off the old plaster so we could put rockwool in and plasterboard over. WestonDave is right about needing a decent amount up in the loft, ours had a token amount and is about to get a load more. A good way of telling if you have enough is wait until it snows, if the heat is escaping then the snow on the roof will melt (ours never had much snow on!), a well insulated roof will have a lovely thick covering of snow. Of course it would be nice to be insulated before it gets that cold.

JenniO

Hi
As I had the loft boarded out myself years ago I made sure there was really good yellow insulation under the floor boards and all down the sides where the eaves are.

I can definitely see the back sides of the slate tiles. In between the tiles going in vertical stripes is some sort of greyish cement looking stuff that looks really old. We get a lot of black 'slate' dust in the loft on top of things. The house was built in 1927. And surprinsingly never had a leak and no tiles have ever blown off even here in the north east's very strong winds.

jen

jimbo_the_jetset

All sounds ok then. I wouldn't bother going to the expense of redoing roof to put felt on. If it gets to the point where you are getting damage you might be able to get an insurance claim, but not really worth the money to do it before then.

And remember, the only stupid question is the one you don't ask.

LandyAndy

Just to confirm what others have said. My first house was built in the 1930's and had no felt behind the tiles. I asked my grandfather, who was a tiler, and he confirmed that this was the construction method used at that time. If your house is post 1950's expect to see felt.

ormus

there are huge numbers of homes with no insulation betweent the rafters. mine is the same. i can see the tiles. but if the loft floor is well insulated its ok.
assuming the loft is just used as storage space.

think the recommended minimum thickness is now 270mm?
only 30% of homes have insulation of more than 150mm!
also, 300mm will cut down on heat loss by a huge margin.
ie 0.20 watts loss per sq m compared to 25 watts per sq m for 150mm!