Pitched v Flat roof - Cost comparisons

[Skyedriver]

I know pitched roofs are more long lasting and almost always more aethetically pleasing and fit in with the house more readily and if I had loads of money it would be a tiled pitched roof on the extension I am intending to add to the new bungalow we are purchasing.
The extension is around 3metres x 8metres, and sits on the side of the bungalow. Others on the estate have gone flat roof but I want to do this once and right, cost permitting.
The pitched roof could T into the pitch of the bungalow and could go in at the flattest gradient allowable 22 degrees (?) and at 450 c/s I would only need 7 trusses plus a few other bits and pieces. Insulation would be rolls of f/glass rather than Kingspan which might be cheaper too. Plasterboard ceiling the same. Other cost considerations but I can budget for them (simple Velux roof lights rather than a pitched glass skylight but I can sort them costs).

So in general what are the cost differences, my guess is twice as much but am I underestimating drasically and what would it cost to construct a built up felt roof at that size.

Thanks everyone.

[Si 330]

Budget for repairing the flat roof every 10 to 12 years.

[Skyedriver]

I know, had them before but there is so much to do and budget is stretched a bit. Tiles is a "fit and forget" it's just the cost situation. If its only a grand more then great if its ten grand more then I need to forget the windows, boiler and sell a kidney.

[Busamav]

Take in to account the loss of property value with a flat roof , then the pitched roof will be so much cheaper .

If you have the option to pitch , do not go flat roof for maintenance and aesthetics reasons .

[Trevelyan]

Also check the small print of house insurance when dealing with flat roofs. My house has got a flat roofed extension, and although they don't tell you unless you ask when you dig into the small print a lot of insurance companies place restrictions on flat roofs. A lot of insurance companies seem to use the rule that if the flat roof is more than 25% of the total house footprint you either have to pay a higher premium, or get refused altogether.

Although my extension is only about 4m x 4m, because it's strapped to the back of a 2 bed terrace I fell on the wrong side of this rule, and had a nightmare getting sensibly priced insurance as a result. I ended up having to insure it through the same company which were providing me the mortgage, who couldn't really refuse as it was in effect their asset I was insuring.

[blackcab]

A flat roof done correctly will last 30 - 40 years providing you use high performance materials and its installed correctly, if its a new build on a high performance felt roofing spec you are probably looking at about £65 -£75 per m2 including:
Plywood Deck
Vapour barrier
Insulation
Vented layer
Mineral cap sheet.

You can have a slight fall to the roof ensuring water runs away from the building.

There are other systems available such as Urethane and fibreglass systems but to be honest Felt is still the best way in my opinion.


if you need any info just drop me a line or take a look at our website
www.garlandukltd.co.uk

[mrmaggit]

If it's only got a three metre span, don't bother with trusses, just use standard joists onto a wallplate. 22.2 degrees is a good average for most standard roof tiles, about 320-ish tiles for that area, 1 roll of breathable felt, 100 lin metres of 25x50mm lath, 7 metres verge strip, 8 metres of felt support, 8 metres of 10mm eaves vent, 8 lin metres of abutment vent, 32 sq.mtr. some lead to flash over the abutment vent, foil insulation, plus guttering which you'd need anyway.

Off the top of my head, (I'm not at work so the material price is from memory) around £500 plus VAT, plus joists, lead, rafters, nails, insulation (up to you what thickness), plasterboard, guttering, plus a bit for consumables. Some of that you'd need on a flat roof anyway.

It'll be more on the Isle of Skye, though, but so will the flat roof materials. Always go pitched if you can.

HTH

[Skyedriver]

Thanks guys, been around the estate and others today and the pitched/tiled rof looks so much better although everyone on the estate our new bungalow is on seems flat roofed, every one a different design.
Oh and Mr Maggit, sorry, the new place is in N Yorks, but still keeping our Skye home. Couldn't sell it too many memories.
Anyone need a kidney or right arm?

[liverlad]

Skyedriver said:

I know pitched roofs are more long lasting and almost always more aethetically pleasing and fit in with the house more readily and if I had loads of money it would be a tiled pitched roof on the extension I am intending to add to the new bungalow we are purchasing.
The extension is around 3metres x 8metres, and sits on the side of the bungalow. Others on the estate have gone flat roof but I want to do this once and right, cost permitting.
The pitched roof could T into the pitch of the bungalow and could go in at the flattest gradient allowable 22 degrees (?) and at 450 c/s I would only need 7 trusses plus a few other bits and pieces. Insulation would be rolls of f/glass rather than Kingspan which might be cheaper too. Plasterboard ceiling the same. Other cost considerations but I can budget for them (simple Velux roof lights rather than a pitched glass skylight but I can sort them costs).

So in general what are the cost differences, my guess is twice as much but am I underestimating drasically and what would it cost to construct a built up felt roof at that size.

Thanks everyone.

[liverlad]

Skyedriver said:

I know pitched roofs are more long lasting and almost always more aethetically pleasing and fit in with the house more readily and if I had loads of money it would be a tiled pitched roof on the extension I am intending to add to the new bungalow we are purchasing.
The extension is around 3metres x 8metres, and sits on the side of the bungalow. Others on the estate have gone flat roof but I want to do this once and right, cost permitting.
The pitched roof could T into the pitch of the bungalow and could go in at the flattest gradient allowable 22 degrees (?) and at 450 c/s I would only need 7 trusses plus a few other bits and pieces. Insulation would be rolls of f/glass rather than Kingspan which might be cheaper too. Plasterboard ceiling the same. Other cost considerations but I can budget for them (simple Velux roof lights rather than a pitched glass skylight but I can sort them costs).

So in general what are the cost differences, my guess is twice as much but am I underestimating drasically and what would it cost to construct a built up felt roof at that size.

Thanks everyone.

be careful on your degrees,anything less than 44 degrees have to be rosemary tiles!

[-Pete-]

We had five or six quotes from builders, they all said flat roof but we weren't keen, then one said he could do a pitched roof at no extra cost, and the result is so much nicer. I think they're Marley Sandringham, work down to 22 degrees, so much better than a flat roof IMO.

[satans worm]

Just an idea while you are at the planning stage, the advantage of a bungalow is that you can vault the roof and put in skylights which really make a difference to a room, can add alot of character to an otherwise standard box IMO.
Even if you have a flat roof you can add skylights, I remember seeing pitched victorian style ones, or it you like a more modern look, that one in grand designs that slid across via remote control like a giant sunroof, although i seem to remember it cost a fortune too!

[Harry Flashman]

Flat roof - beautifully decked roof terrace with barbecue and nice potted plants.

Worth it.

[mrmaggit]

liverlad said:

Skyedriver said:

I know pitched roofs are more long lasting and almost always more aethetically pleasing and fit in with the house more readily and if I had loads of money it would be a tiled pitched roof on the extension I am intending to add to the new bungalow we are purchasing.
The extension is around 3metres x 8metres, and sits on the side of the bungalow. Others on the estate have gone flat roof but I want to do this once and right, cost permitting.
The pitched roof could T into the pitch of the bungalow and could go in at the flattest gradient allowable 22 degrees (?) and at 450 c/s I would only need 7 trusses plus a few other bits and pieces. Insulation would be rolls of f/glass rather than Kingspan which might be cheaper too. Plasterboard ceiling the same. Other cost considerations but I can budget for them (simple Velux roof lights rather than a pitched glass skylight but I can sort them costs).

So in general what are the cost differences, my guess is twice as much but am I underestimating drasically and what would it cost to construct a built up felt roof at that size.

Thanks everyone.

be careful on your degrees,anything less than 44 degrees have to be rosemary tiles!

Utter crap, if you can't be helpful, stay in the bar.

[Globulator]

Skyedriver said:

my guess is twice as much but am I underestimating drasically and what would it cost to construct a built up felt roof at that size.

In my experience pitched roofs are cheaper. You just need the wooden structure built, then felt, battens and tiles, QED, all done. Plus you do not really want a swimming pool on the roof, let gravity work for you and carry the water away.