Quick summary: Are very high temperatures (40C+) a problem in a loft? And is there a way to reduce that temperature?

--

For extraordinarily geeky reasons, I've been doing some temperature monitoring around my first floor flat. I've recently put a load of loft insulation in, and it's been really successful keeping us warm during the recent cold snaps.

Now it's warming up, I'm also seeing the loft insulation doing an excellent job. Yesterday, for example, was a sunny day, with outside air temperature reaching about 15C. The flat was a comfy 20C, but the loft got up to about 25C (even though it's reasonably well ventilated up there).

My concern is that in the height of summer, the loft will be up to 40C or more (although the insulation should keep the flat nice and cool).

My questions are:

1) Is a super-heated loft a problem? Does that excessive heat cause any sort of damage to the woodwork or the roof?
2) Is there a way I can cool the loft down? We use it for storage, which is tolerant to temperature changes, but super-high temperatures probably aren't good in the longer term.

One idea was to insulate between the rafters, under the roof? That would keep the sun's heat baking the tiles out of the loft, wouldn't it? But would that stop the loft 'breathing'?

Another idea would be to use the (otherwise unused) chimney(s) - I could add in some vents to suck in some outside air (or push air out). That seems rather over-elaborate though...?

Hi,

To be honest that sound,s normal i've worked in our loft in the summer month's and it is absolutely stifling, the sun heats up the roof surface and the insulation traps the heat.
storage should not be a problem although it depends on what you are storing

_________________
If you think nobody cares, try missing a couple of payments..

yep nothing to worry about like the other 20 million or so houses with a roof and full insulation just wait for the 50 to 60 degrees on a very hot day

_________________
we are all ------------------still learning

Okay, good to know the heat isn't going to be a problem for the house. Thank you for that.

So how about some sort of 'cooling' solution? Can I either:

1) Insulate the roof itself to avoid getting the heat in the first place
or
2) Vent the loft with outside air somehow?

Obviously, avoiding getting the heat in the first place would be the best idea - but is it 'safe' to do?

I think this needs more investigation as the temperature should not be that high for the following reasons. Firstly the insulation should stop heat rising from the heated rooms below and secondly the outside temperature have not been high enough to build up heat like that.

All lofts are designed to allow the circulation of air so hot air rises and as it is cooler outside it would vent out leaving cooler (heavier air) in its place.

Is there an expansion tank up there and is the heating/hot water system pushing steam out due to a thermostat problem??

I went in my loft and it is bleeding freezing.

However, if you are posting from Barbados then this might explain.

DWD

i am assuming you want to use the space for more than just storage if you want to spend around £200 insulating to keep it cool

_________________
we are all ------------------still learning

it was 15 degrees here this week which equated to 26 degrees in direct sunlight when i placed the thermomiter on the fence so 25 in a loft would be nothing very special if the suns warming it all day
i am assuming its the daily highs and lows that are measured!!

_________________
we are all ------------------still learning

I'm pretty confident there's nothing untoward going on in the loft (no heaters, hot tanks or anything). I do want to put a home media server and my wireless router up there, which will generate a tiny amount of heat, but more worryingly won't like it if the temperature goes up to 40C+ (actually, technology starts to get a bit annoyed if the temperature goes above 25C, but that's another matter ;-)

The problem really only happens when the sun bakes down on the roof. Right now, it's pretty overcast with the occasional sunny spell, with 15C outside temperatures (in the shade) and the loft is at about 21-22C. Yesterday, as I say, in nearly day-long sun, it got up to about 25C - but we're not exactly in the height of summer yet ;-)

I'm really just looking for what options I've got. I've been reading some building regs, which suggest I can insulate between the sloping roof rafters, so long as I leave 50mm between the insulation and the tile felt, and leave a gap at top and bottom for ventilation. I haven't measured the rafters, but from memory they're 100mm, so this looks quite possible. The stuff I've found talks about putting a polythene moisture barrier on the back of the insulation, and putting thermal plasterboard over the top. I don't need to make it look nice - so can I just skip those two steps and just use some batten or something to hold the insulation in place?

As you say, I'm possibly going to spend a few quid on this, so I don't want to do that if it doesn't really work very well, or if it causes any sort of problems up there. Any guidance would be much appreciated!

Why not put the money towards a cooling solution for the equipment housings ?Must be easier to control the temperature of a smaller area than a biggger area. Build a decent sized box for all your gear and add some thermostat controlled fans to it.

Yeah - but fans don't actually cool anything. If you blow 40C air over something, it 'cools' it to 40C :-(

I was wondering if I could suck some outside air from the eaves and blow it on the general direction of the computer (so roughly what you're suggesting), but I thought that was possibly a bit elaborate, and does nothing for the stuff we're storing up there. Insulation may turn out to be too expensive or whatever, but it seems like it could be the most effective option (although I'd like to know a bit more about it before shelling out for it).

the trouble you have is attics can be horrible dusty dirty damp hot cold places

realy rather hostile enviroment to place sensitive electronic in

do you not have a wardrobe/ cupboard/area upstairs ]understairs you can use!!!

_________________
we are all ------------------still learning

From experience - don't store guitars or wine there.

that's really all I have.

sorry.

I wouldnt be concerned either. Every loft i have ever been in has been warm. Only thing i would double check, is that theres is adequate ventilation at the eaves. Insulation shouldnt be pushed in there in most most cases i think

_________________
Why isn't the number 11 pronounced onety one?

Thank you all for your help on this.

Having done some reading around some of the ideas here, I think I'd like to give a bit of insulation a go. I'm thinking about something like this:

http://www.homebase.co.uk/webapp/wcs/st ... ber=127033

It seems I can pretty much just staple this stuff across the sloping roof rafters (with a decent gap at the top and bottom for ventilation). I was thinking I'd just get a couple of rolls and do the South facing roof and see if it seems to make a difference. I reckon I can probably do that with just a couple of rolls of this stuff, so probably spend about £40 + a couple of hours of my time. If it works, then I'll look at doing the rest.

One of the comments at Homebase also mentions that because it's shiny, the light in the loft works better with this stuff too ;-)

in MY HUMBLE OPINION this is a daft idea an attic is a hostile enviroment
every thing that electronics dont like are up there extremes of hot and cold dust damp and condensation

putting up a thin plastic layer wont stop the highs and lows it will just slow it down by a couple off hours it will still reach 30 and 40 degrees plus

it will also cause condensation to collect and drip like rain

if i am misunderstanding this problem as in
is this a distribution system for the house or is it a system you veiw where installed where you intend sitting up there with a few mates and a few beers!!!

_________________
we are all ------------------still learning