Curved roof options

techspec

Hi,
Recently recieved planning for renovation of old building and construction of extention. Planners forced me to have a curved roof on extention.
I need to get ideas on what is available and ballpark costs?
Any ideas?

sinnerboy

what size
curved on plan ?
curved in elevation ?
what finishing material ? felt , asphalt , tiles , copper , ?

Mellor

sinnerboy wrote: »

what size
curved on plan ?
curved in elevation ?
what finishing material ? felt , asphalt , tiles , copper , ?

Same questions please.


Its kinda funny, you see this as being forced, but alot would see it as a great opertunity.
Can you posted the exact wording of the condition, please.

hippychippy

Don't forget zinc.

techspec

sinnerboy wrote: »

what size
curved on plan ?
curved in elevation ?
what finishing material ? felt , asphalt , tiles , copper , ?

Sinnerboy,
The building is 13 m by 6 m and the curved on elevation, finishing material not specified.

I have to submit finish material with commencement notice accompanied by the notorius planning contribution,

I need to research options in terms of cost, I dont want to spend a fortune on a state of the art roof and have to sacrifice on the interior finish?

I have came accorss Tegral twn skin but dont know..

ircoha

techspec wrote: »

Hi,
Recently recieved planning for renovation of old building and construction of extention. Planners forced me to have a curved roof on extention.
I need to get ideas on what is available and ballpark costs?
Any ideas?

Forced ma, the FPP grant would have been as a result of a planning app that included the curved roof or did your architect just shove it in?.
The patent on this has expired http://pahlai.notlong.com

Can we have a link to the FPP to see the plans?

techspec

Mellor wrote: »

Same questions please.


Its kinda funny, you see this as being forced, but alot would see it as a great opertunity.
Can you posted the exact wording of the condition, please.

No specific wording in conditions but here is background. This is a renovation/extension project. I have an old disused 3 story stone building which was originally a coach house. I was adding an extention to it. My original design attempted to retain the coach house and have the extension in keeping with the old design.

However, upon planning review, they requested a more Contemporary design for the extention which has developed into a curved roof and timber clad external walls

Cheers

sinnerboy

sorry but i still have problems 'seeing' this

can you attach a pdf

or if you give local authority and planning ref no contributers can view scanned drawings

250882

from reading your posts you (or your architect) designed the contemporary curved roof and submitted it for planning and now you are annoyed with the LA because it got granted?
There are loads of materials on the market that can form a curve but as they are not as common as slates or tiles they will probably be more expensive and tradesmen will need to be sourced that have experience working with them. Its very hard to picture this curve from your discription but if it is a wave or convex curve shape on elevation then probably, copper, zinc even lead or a proprietry roofing membrane like trocal or sarnafil which can be dressed to look like the above would be most suitable.

Mellor

250882 wrote: »

There are loads of materials on the market that can form a curve but as they are not as common as slates or tiles they will probably be more expensive and tradesmen will need to be sourced that have experience working with them. Its very hard to picture this curve from your discription but if it is a wave or convex curve shape on elevation then probably, copper, zinc even lead or a proprietry roofing membrane like trocal or sarnafil which can be dressed to look like the above would be most suitable.

Quick comments, Slates can do curves, its non standard, but teagral will do it. Coper would be my prefered, followed by zinc.
Trocal or similar can also work, and look decent, and of course save cost. But only suitable for high level, not on single story, looks less fake at a height.


As for the source of the problem, I can see why you wanted to match the extension to the existing, alot of laypeople think this is best. But in fact the opposite is true, separate old and new. Off the top of my head, look at some of the recent hotels converted from 18/19th century estate houses.

As for construction, alot of people are not aware that a curved surface can be made from straight materials. Cylinders, cones, arches, hyperbolic parabolids, all curved, all made from straight members.


How complex is the curve, i'd go to town on it.
Can you post a planning ref

250882

I was going to mention about slates being able to do gentle curves but if the curve is how I imagine it then I would worry about the gradient at the ridge, youd need some serious underlay and then it would be punctured by fixing the slating battens. Copper would definately be the nicest but its a bit pricey

I definately agree with you about seperating old and new it preserves the existing structure much better and defines the extension, a lot easier aswell as you dont have to get new finishes to try and look like old ones.

Slates

250882 wrote: »

I was going to mention about slates being able to do gentle curves but if the curve is how I imagine it then I would worry about the gradient at the ridge, youd need some serious underlay and then it would be punctured by fixing the slating battens. Copper would definately be the nicest but its a bit pricey

I definately agree with you about seperating old and new it preserves the existing structure much better and defines the extension, a lot easier aswell as you dont have to get new finishes to try and look like old ones.

Slates will work fine on a curve depending on the pitch and the radius. All slated curved roof are counterbattened to provide a run off for water and to help with the puncturing of the underlay

250882

Maybe we're not thinking of the same senarion but the slate roof curved on elevation would mean that on the apex the slates would be completely flat and for a consiterable portion of the roof at a pitch lower than 22.5 degrees and therefor are liable to allow a lot of water penetrate and create a danger of being blown off.
Slates on a roof that is curved on plan (e.g curverd walls below) would not prove too much of a problem as long as they are counterbattened etc. as you describe above

Mellor

250882 wrote: »

Maybe we're not thinking of the same senarion but the slate roof curved on elevation would mean that on the apex the slates would be completely flat and for a consiterable portion of the roof at a pitch lower than 22.5 degrees and therefor are liable to allow a lot of water penetrate and create a danger of being blown off.
Slates on a roof that is curved on plan (e.g curverd walls below) would not prove too much of a problem as long as they are counterbattened etc. as you describe above

You not thinking outside the box, get a better curve.
The apex doesn't need to be at the same height as the ridge, it will of course be closer, but the min pitch can be maintained, it will then be steeper at the edges.

I am pretty confident that I could design this in such a way that it was fine for slates, no different than a conical roof. And would look good too .

Slates

What type of a curved roof are ye talking about ??

A haybarn type curve,(this cannot be done with slate without major expence)
or
A roof that is curved on plan (the wall plate curves)

Mellor

Slates wrote: »

What type of a curved roof are ye talking about ??

A haybarn type curve,(this cannot be done with slate without major expence)
or
A roof that is curved on plan (the wall plate curves)

It is curved on elevation (similar to haybarn),
but I maintain that it can be done in slate. Its simpler than it looks at first. If the two gables of a haybarn were at different heights, then there is an adequet fall from gable to gable to maintain 20-25 deg for slates.
The curve can be then flatened so that is is prehaps 75 deg on elevation (as opposed to 180), the abbuting side could even be flatten totally.

Any way, sheet metal is a better choice than slates, brief was contemporary

Slates

Mellor wrote: »

It is curved on elevation (similar to haybarn),
but I maintain that it can be done in slate. Its simpler than it looks at first. If the two gables of a haybarn were at different heights, then there is an adequet fall from gable to gable to maintain 20-25 deg for slates.
The curve can be then flatened so that is is prehaps 75 deg on elevation (as opposed to 180), the abbuting side could even be flatten totally.

Any way, sheet metal is a better choice than slates, brief was contemporary

You would have to go continent for a slater to do that job, most Irish slaters would eat the roof before tackling a roof like this.

You would need to taper cut both the side and the hed of the slates to do this job.

A standing seam roof would be the way to go

Mellor

Why would you need to cut the slates?
The fall is parrallel to the slates, The roof is not curved on plan. slates are laid straight.

If you had a more complex design that required a curved plan, that still isn't a problem for slates. Curved roofs are common enough

kadman

250882 wrote: »

Maybe we're not thinking of the same senarion but the slate roof curved on elevation would mean that on the apex the slates would be completely flat and for a consiterable portion of the roof at a pitch lower than 22.5 degrees and therefor are liable to allow a lot of water penetrate and create a danger of being blown off.
Slates on a roof that is curved on plan (e.g curverd walls below) would not prove too much of a problem as long as they are counterbattened etc. as you describe above

Thats the way I picture it too. Are the 2 curved gables the same profile and the same height. As I see it as the slates go progressively up the curve their angle decreases.Any pdf of the elevations.

kadman

techspec

sinnerboy wrote: »

sorry but i still have problems 'seeing' this

can you attach a pdf

or if you give local authority and planning ref no contributers can view scanned drawings

I dont have a pdf or any electronic form of the drawings, I will scan them in. One of the other contributers described it perfectly, its a haybarn roof but with a wider radius (gentler curve).

Anyway, what I need is to be pointed in the direction of suppliers/installers

At this point I have ruled out slates due to possible leakage at the ridge where the slates would be almost horizontal.



Thanks for e

kadman

Just looking at Grand Designs on channel 4. Curved roof made in sections from concrete, with internal reinforcing, pipe work, and insulation, 2 tons each section.

kadman

Mellor

techspec wrote: »

I dont have a pdf or any electronic form of the drawings, I will scan them in. One of the other contributers described it perfectly, its a haybarn roof but with a wider radius (gentler curve).

Anyway, what I need is to be pointed in the direction of suppliers/installers

At this point I have ruled out slates due to possible leakage at the ridge where the slates would be almost horizontal.

Well as pointed out a haybarn with a flat ridge won't work with slates,
your better off, go wit copper or zinc.

What is the structure, timber, steel, concrete.
A metal deck between curved trusses would work easily.

kadman

Well done 250882....bang on the button:cool::cool:

kadman

roofer

Slates wrote: »

You would have to go continent for a slater to do that job, most Irish slaters would eat the roof before tackling a roof like this.

You would need to taper cut both the side and the hed of the slates to do this job.

A standing seam roof would be the way to go

lets not sell ourselves short boys. once the carpentry work is good and the roof is struck out properly its quite straight forward but time consuming. both sides of the slate needs to be cut and the slate width should never be less than 6 inchs. any less than that and you are below the threshhold of water penetration. it would be a shame to put slates on the roof and rely on the felt underneath to keep the water out. there are plenty of irish slaters who can do this job. the problem is getting paid the right money to do it!!! roofs like that dont come cheap. when the price is dismal so is the work because the tradesman will have to rush it to make money on it. i personally wont touch a curved roof because of two reasons
1. no one would pay the money i would ask for.
2. a curved roof with good carpentry work is hard to come by

when it comes to curves and circumferences, you get what you pay for.
bottom line, i would go with copper or zinc.

kadman

roofer wrote: »

lets not sell ourselves short boys. once the carpentry work is good and the roof is struck out properly its quite straight forward but time consuming. both sides of the slate needs to be cut and the slate width should never be less than 6 inchs. any less than that and you are below the threshhold of water penetration. it would be a shame to put slates on the roof and rely on the felt underneath to keep the water out. there are plenty of irish slaters who can do this job. the problem is getting paid the right money to do it!!! roofs like that dont come cheap. when the price is dismal so is the work because the tradesman will have to rush it to make money on it. i personally wont touch a curved roof because of two reasons
1. no one would pay the money i would ask for.
2. a curved roof with good carpentry work is hard to come by

when it comes to curves and circumferences, you get what you pay for.
bottom line, i would go with copper or zinc.

Hi Roofer,

I assume by cutting both sides of the slates, your roof is curved in plane, and that both gables are not paralel to each other. I thought the curvature of the roof was , each gable had a curved top section as viewed from end elevations, and that the ridgeline in plan was at 90 degrees to each gable.

Pity there was no pdf posted to get a better idea of which option was required.

As in all curved timber projects, they command a premium price.

kadman

MOBH

Guys - could you tell me is there much difference in price for a standard roof and curved? We have one section of our build curved and one section standard. Worried that the curved part will be v expensive. We are only going for planning permission at the moment and haven't submitted our final submission yet. Just looking for some advise on it, TIA

BryanF

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