Can a pitched roof be designed with max 2.5m height?

[indus]

Hi

Just wondering whether anybody can help with this.

I'm going to be constructing an outbuilding that will be 7.5m x 4m, because it will be 1m from my boundary it can have a max height of 2.5m in line with PD rights.

It will have cavity walls


Is it possible to get some kind of pitch at that sort of height such that I also still get good head height inside?
I'm just trying to avoid a completely flat roof as they don't look very nice.

Thanks

 

[freddiemercurystwin]

Depends what you call good head height inside. With that pitch like that though (aorund 11°) you will not be able to use a traditional roof tile or slate although if you did you could try increasing headlap or other other modifications to increase its weatherproofing though.

 

[stuart45]

A friend of mine has just built a large porch for someone with a similar pitch using large fibre slates and a good headlap. He also double felted it.
He's not a man to do a bodge job, so I reckon it will be OK.

 

[noseall]

Laying roof tiles on an 11 degree pitched roof will not only be pointless but will also look horrid.

Bite the bullet and deal with a flattie.

 

[simonjay]

Laying roof tiles on an 11 degree pitched roof will not only be pointless but will also look horrid.

Bite the bullet and deal with a flattie.

If you've got the cash put a zinc roof on it. They are all the rage

By the way, I did a 12 degree tiled pitched roof (mono-pitch, but joining onto party wall) using forticrete centurian tiles (they have baffles against driven rain etc). It looks fine in context, but I agree not sure about a stand alone roof at that angle.
Too low pitch for tile or ridge vents, I had to put a big hole in the gable to vent it !

Simon.

 

[indus]

Thanks, pitched roof is out then by the sounds of things.

I'll look into zinc roofs.

I suppose all I can do is try some tricks to improve the aesthetics like perhaps a false pitch?

 

[freddiemercurystwin]

Technically once a roof is 10° or less it is a flat roof. Zinc is very nice (well I like it) but may be a little industrial or some. This chap //www.diynot.com/network/hardmetalking seems to know his stuff if you want to explore that option further.

 

[jeds]

Forticrete Centurion. go down to 10°. Used them recently. I woudn't say the result is fantastic but it's not that bad and they are functional.

Untitled

• jeds
• 16 Sep 2011
• 1

 

[theoldun]

By putting door in flank wall and plates at 1875, and raised tie joists at 2400 you could get 16 degree pitch which will take at least 4 types of Redland profile tiles.
Overall building 4000
Overall plate 3600
Run 1800 less half ridge = 1775
Overall height 2500 less plate height 1875 = 625 rise
625 rise less HAP of rafter say 66 = 559
559 less ridge tile say 50 = 509
There for rise = 509, run = 1775, hypotenuse (setting out pitch line) = 1847 = 16 degrees.
Regards oldun

 

[indus]

Forticrete Centurion. go down to 10°. Used them recently. I woudn't say the result is fantastic but it's not that bad and they are functional.

Untitled

• jeds
• 16 Sep 2011
• 1

Thanks Jeds.

Is the highest point of that extension 2.5m?

 

[indus]

By putting door in flank wall and plates at 1875, and raised tie joists at 2400 you could get 16 degree pitch which will take at least 4 types of Redland profile tiles.
Overall building 4000
Overall plate 3600
Run 1800 less half ridge = 1775
Overall height 2500 less plate height 1875 = 625 rise
625 rise less HAP of rafter say 66 = 559
559 less ridge tile say 50 = 509
There for rise = 509, run = 1775, hypotenuse (setting out pitch line) = 1847 = 16 degrees.
Regards oldun

Thanks Oldun, excuse my ignorance as I'm not in the trade

1) Are you saying the door must go in the 4m width dimension rather than the 7.5m dimension for this to work? (Not sure what you meant by flank wall)

2) With the example you give above what would the internal head room be, assuming a plasterboarded finish?

Many thanks

 

[theoldun]

Indus.

Reading your questions has made me think I have dropped a clanger here.

Give me a couple of hours and will come back to you.

oldun

 

[jeds]

Thanks Jeds.

Is the highest point of that extension 2.5m?

No, it's about 2750. But there is scope to lower the eaves tight to the door head which would get you close. Also that extension is 3m from eaves to the highest point where you would be looking at 2m. If you could put the door in the gable wall you could go lower still. The ceiling would be e bit low close to the external walls but in practice nobody really ever stands that close to the wall. Anywhere away from the wall it would be ok.

(when oldun referred to the flank wall I think he meant the gable wall)

 

[^woody^]

Why can't you excavate lower and lower the floor?

Or why not just apply for planning permission and get the roof you want? That would seem the obvious thing to do

 

[indus]

Why can't you excavate lower and lower the floor?

Or why not just apply for planning permission and get the roof you want? That would seem the obvious thing to do

Lowering the floor would mean a large step down when entering wouldn't it?

I'm not sure this would be practical for a garden outbuilding. For example getting heavy/large things in or out ie BBQ, etc would be very difficult.

I could go for PP but then

1) How says PP would allow it? I'm building 1m from my boundary and if PD doesn't allow over 2.5m then there is a good chance that PP won't either.

2) There are loads of trees around (including protected) and so the council will ask for aboriculturists reports and all sorts. All extra cost

3) If PP was turned down/delayed then because my area may turn into a conservation area in the next 3-4 months I would then also lose PD rights and be even further restricted.

4) My builders will be on site from next week starting my loft conversion. If they can get going with this whilst they are still on site it reduces the cost for me.

Cost is not the over riding concern though, I am happy to spend more to get the right aesthetic result, but I think I will have to stick with 2.5m so that I can crack on with the work.

Thanks