# Flat roof for workshop?



## colinc (26 Jul 2012)

Hi,

hopefully, I am going to be building a new workshop soon. I am torn between the simplicity of not needing planning permission if I stay below 2.5m height and my preference for a pitched roof. I was wondering what the team thinks about flat roofs? It's a long time since I was involved with them and single membrane and butyl rubber have come along since I really took any notice. I am thinking in terms of a 6.6m x 4.5m floor area.

Any views?

Colin


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## Wildman (26 Jul 2012)

only answer for a flat roof these days is fibreglass. no leaks job done. Slightest camber to the drainpipe or turn it into a watercress pond, hee hee


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## Grahamshed (26 Jul 2012)

My workshop ( 8.5 X 6.2 metre including a veranda) has a flat roof with approx 300mm slope back to front. It was felted but sprung a few small leaks so I have just,yesterday, taken delivery of a rubber roofing one piece membrane with an expected 40 year life which will see me out twice over.


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## Harbo (26 Jul 2012)

I opted for an EPDM roof on mine a few years ago - 25yr guarantee.

Rod


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## Doug B (26 Jul 2012)

colinc":3pa7jztp said:


> I am torn between the simplicity of not needing planning permission if I stay below 2.5m height and my preference for a pitched roof.



Is that a local reg?

It`s usually around 4 to 4.5 m on a pitched roof before planning is required, or at least was when I built mine.


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## fluffflinger (26 Jul 2012)

I'm with Doug, check with your local authority but you should be able to go to at least 4 m without requiring planning permission. 

I think you would be missing a trick if you don't go for a pitched roof. . . . . . . . . . . . . .great storage. 

I have built storage in three separate sections of my roof space, one either end and one centrally, you will never regret this extra space trust me. 

I also improved on my storage space by making my roof a Gambrel style http://www.easyrafters.com/gambrel.htm thus creating even more space closer to the eaves, looks cool too  .

Whatever you are planning to put in there make it as big as you possibly can, if for no other reason than it makes for more space to work in and that's a pleasure, wish I'd been braver when I built mine.


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## colinc (26 Jul 2012)

Hi, thanks for the comments.

My understanding is that within 2m of the boundary it has to below 2.5m: http://www.planningportal.gov.uk/permis ... /miniguide 

Unfortunately I don't see a way of fitting in what I want and maintaining 2m from all of the boundaries, that is too wasteful of space. The benefit of having roof space wasn't lost on me.

Am moving towards thinking that I may just put an application in for a pitched roof, I can always back pedal to what is permitted development with a flat roof if they turn me down.

regards,

Colin


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## fluffflinger (27 Jul 2012)

Colin 

An eminently sensible plan I think. 

I bet if you took a straw pole of those that have built their own workshops and could have (space and finance permitting) built bigger I bet there are many like I who wished we'd tacked on a bit more. 

Let's be honest we mostly are accumulators of stuff that we can't possible throw out as it "might" come in handy down the line.


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## sw_edge (27 Jul 2012)

If you want to build without pp and are thinking of staying under 2.5m to do so I think you may have a problem with your floor area which I understand to be restricted to 15m2?


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## Grahamshed (27 Jul 2012)

When I built my shed I designed it to be 24ft X 11 ft internal measurements with a double skin wall ( so add just under 2 ft to each direction ) with a 5ft plus veranda along the long side, so it would be JUST inside the no planning permission regs. It is a flat sloping roof about 9ft or so high down to about 7ft 4 ish by the time it gets to the end of the veranda. The high side is 6 inches from the boundry.
Despite discussing it with the neighbours beforehand someone somewhere reported it to the council and someone came round to check. He measured it very carefully, said I was 1 inch inside the regs and that, with the size of the garden I could build three more if I wanted to. He left with both of us smiling.

Incidentally, with being so close to the boundry the regs say the building has to be largely fireproof.


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## colinc (27 Jul 2012)

> If you want to build without pp and are thinking of staying under 2.5m to do so I think you may have a problem with your floor area which I understand to be restricted to 15m2?



Hi, no, you can use up to 50% of your garden area for sheds etc., under permitted development but if closer than 2.5 m from the boundary you have to keep below 2.5m overall height (different rules apply in Scottyland). Permitted development is quite generous really. 

The 15m2 limit is for building regs on outbuildings, greater than that and/or <1m from the boundary you need building regs approval. If >1m from the boundary or closer if substantially non-combustible, you may have up to 30m2 floor area. After that or closer to the boundary you need to get approval from building control and they may be flexible according to the situation of what is on the boundary.

In my case I would like to:
1) go closer than 1m to the boundary and just leave a maintenance space between
2) have timber cladding although I would be happy to fire protect from inside to out adjacent to the boundary.
3) have a pitched roof - cedar shingle preferably. The orientation would also make it suitable for solar PV panels at a later date.

Because this is a 'bottom of the garden' project I don't think the planners will really have too many issues as I am designing it to fit in well anyway. I think perhaps I'll see what sort of vibes I get from them before making any firm decisions. The points about going for size are well made, although I was planning another store building for the junk, this is MY workshop!

Keep the ideas/info coming though - shed building is a popular subject here.

Colin


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## jack55 (31 Jul 2012)

I had the same dilema, and opted for a flat roof. Mine has 4" polystyrene between the joist which leaves the 2" air gap above, then membrane, OSB membrane and rolled steel sheeting. Works a treat gives me good headroom inside and keeps it within the planning regs. Thought about the one piece rubber but wasnt sure how it would stand upto birds pecking on it.


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