Installing heater under a flat roof for snow?

I'm bulding a flat roof, with a hole for water to drain out of but what if lots of snow collects on there and the drain hole ices up?

At the least melting snow could find its way up udner the slates and into the house,at the worst the weight of snow could collapse the roof

Could I install some kind of electric heater under it (and on top of the kingspan), how and what would this be (obviously dont want to get hot and burn it down)

[george]
Reply to
DICEGEORGE
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Yes I'm sure you could. Flat trace heating cable and a control thermostat would allow you to fit & forget. If I were going down that route though I think I'd probably go 110V center tapped.

I'm not sure I understand your design, it sounds a little odd. I would have thought a conventional gutter under the lowest side would be fairly immune from drainage problems.

If you do not have a good slope to wherever you are draining, you will end up with pooling and with most coverings this means trouble.

AB

Reply to
Archibald Tarquin Blenkinsopp

Just for my education, what slates can you use on a flat roof? I thought BS 5534 pointed to 20+ degrees and that 15 degrees was the limit even in unexposed areas.

Reply to
Robin

Could you please supply a bit more detail about the roof design, slope (if any) and materials? Also where it is attached to the house?

The obvious answer is to design the roof so that it can support the expected maximum weight of snow.

You also can't make any assumptions about the snow melting, because if the area where you live has cold winters and a high snowfall (I assume it must because you are asking the question) then the scenario you must design for is the snow falling and not melting. Perhaps the snow could sit on the roof for a month or more. Topped up by additional snow fall.

An alternative would be to design the roof so you can walk on it, and then just get up there with a broom and sweep the snow off.

I assume that your concern over the slates is that snow could build up high enough on the flat roof to cover the lowest slates on the adjacent sloping roof? Or does your house have a vertical wall faced with slates?

At first read your concerns seem a little unrealistic so more context is needed.

Cheers

Dave R

Reply to
David

All roofs in the UK are designed with a snow load in mind. Even the sloping ones. It's a distributed load so not as great problem as you might think.

Reply to
harry

You can use any slates. The roof has to have sealed or upstanding joints. There are many different systems.

Flat roof BTW are never flat, there is a slight slope for drainage.

Reply to
harry

Sorry that should read "can't" use any slates.

Reply to
harry

You design your roof for the snow loading in your part of the UK.

An active solution would be unwise as a heavy winter is when your electricity supply is most likely to fail. The passive solution is to make the roof strong enough for the worst case weight of snow and ice.

Reply to
Tim Watts

Of course, if you didn't have that Kingspan in there, heat loss from the house might have melted the snow.

Reply to
polygonum

thanks for advice, photo is at

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and
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the drain hole is in the wall under the orange rope on the right

(not sure exactly how i'm going to do it but this is the time to think about melting ice if itblocks up

We havent had a lot of snow here since maybe 1963 butif climate change changes the gulf stream we may get lots of snow as we're surrounded by sea and quite north.

Building Control are coming on Monday I'm worrying about worst case scenario...

[george]

Reply to
DICEGEORGE

Sounds like a bit of a waste of energy to me. I don't believe this idea is going to work in any case. The snow can semi melt and still clog things up. Where I used to work they had a heated roof car park ramp to stop people getting stuck. Did not work due to uneven heating and it still froze at night. Brian

Reply to
Brian Gaff

"Archibald Tarquin Blenkinsopp" wrote in message news: snipped-for-privacy@4ax.com...

A bit overkill? Whats wrong with 230V and a 30mA RCD?

Reply to
ARW

Are you going to take the covering on the flat roof up under the slates so it's at least 6 inches above the flat bit? If so I don't see how water can get into the house under the slates unless the roof turns into a tank holding water deeper than that.

Reply to
Robin

re: [ I don't see how water can get into the house under the slates unless the roof turns into a tank holding water deeper than that. .] yes, thats what i was worrying about if it fills with snow and ice

re: [ I can't see any flat rooves anywhere - this picture shows two pitched rooves coming together into a valley ]

there used to be 2 valleys and a smaller pitched roof in the middle, now I'm building what i call a flat roof covered with EDPM about 4 meters by 4 meters which you could also call a valley

I think I'm worrying too much, lets see what the Building Control man says tomorrow...

[george]
Reply to
DICEGEORGE

I'd be more worried about the drain hole getting blocked with leaves etc, tbh.

Reply to
Adrian

I'd have thought an off-the-peg heated roof outlet would be the first step if you are that worried.

And that taking the the membrane further up under the slates would be a cheaper than any form of general heating.

Reply to
Robin

" off-the-peg heated roof outlet " sounds interesting .. but google doesnt find anything relevant...

Reply to
DICEGEORGE

"optional heating element"

Reply to
Andy Burns

Google is not the only search engine, and yours are not the only search terms :) In addition to Adrian's link a minute or 2 on Bing gives

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NB I've not used them. I know of them only from an aborted house purchase 3+a bit years ago.

Reply to
Robin

Adrian? Sorry Andy. Put it down to the way front-of-the alphabet names tend all to look alike to this victim of alphabetism ;(

Reply to
Robin

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