Could I have some help please building a pitched roof

[beezo]

Hi guys,

Hope you guys can help advise me with building a pitched roof on my mums flat roof extension. The flat roof is beyond repair and the ply underneath is rotting too. My mum would like a pitched roof put on as it will last much longer than a flat roof. I'm quite handy (bet you hear that all the time) so am going to attempt it myself but would just like some of your opinions on what I propose to do.

I'm going to upload some plans in a moment of the different options I have, none are ideal but I'm limited to what I can do because of a) shape of roof b) next doors extension is too close to my mums extension so I would be unable to fit soffits/fascias and guttering. This side will have to be bricked up.

Will upload some plans shortly, any advice appreciated

 

[beezo]

here you go, hope this works

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• beezo
• 30 Aug 2014
• 1

This is the roof as it stands

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• beezo
• 30 Aug 2014
• 1

This is the ideal roof design I think but because of the neighbours extension, it cannot be done

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• beezo
• 30 Aug 2014
• 1

The is a possible roof design but both the left hand side and right hand side 'gables' would have to be bricked up

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• beezo
• 30 Aug 2014
• 1

This I think is the best design but im not sure how it will look as to get both hips with the same gradient, the beam would have to be installed 3.05M into the roof. would it be possible to decrease this but I assume this will make both hip gradients different

 

[beezo]

Can anyone offer any advice? Would really appreciate the input

 

[freddiemercurystwin]

Some photos of the existing set-up please.

BTW a good flatty will last 20 years. Even then only the covering should require changing if the substructure is done well too. Some metal flat roofs will outlast a pitched.

 

[beezo]

Here you go mate, best I could get

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• beezo
• 31 Aug 2014
• 1

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• beezo
• 31 Aug 2014
• 1

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• beezo
• 31 Aug 2014
• 1

I've uploaded a pic of the current roof tiles on the main house too. Anyone tell the name of them as ideally I would like to put them on the new pitched roof, providing they will work on the pitch

 

[munchingB]

any reason that you are not happy to just do a simple monopitch?

 

[beezo]

any reason that you are not happy to just do a simple monopitch?

Just the fact my mum doesn't want a brick wall or cladding on the side of the roof that can be seen. Would be easier if I did a mono pitched roof but easier is not always better 😄 The other side of the roof we have no choice to do this as it's so close to the neighbours extension but this wall won't be seen anyway.

So what do you think is the best thing to do?
Are 6x2 c16 enough or should I use c24?

 

[freddiemercurystwin]

I don't follow why you don't just replace the flatty tbh. Anyway once you allow for a 150mm flashing under the first floor windows what pitch will you end up with?

 

[beezo]

I don't follow why you don't just replace the flatty tbh. Anyway once you allow for a 150mm flashing under the first floor windows what pitch will you end up with?

Just don't like flat roofs, it's just a personal choice, yes it would be much easier and cheaper but spending a little more time and money will get something that looks atheistically pleasing and watertight
I'm hoping to drop the trusses further into the roof along side the joists to give me a better pitch. I won't know truly the pitch I will get until see what it's like under the felt

A rough estimate would be approx 16 degrees, even better if I can do what I said above. I've seen that Marley Wessex tiles can go down to 15degrees but they aren't my preferred tile choice. Would like to match the existing roof.

 

[theoldun]

If you are doing this for your old mum. we can answer any question you throw at us, however we need the following information.
Width of gap between your extension and next doors.
Are your measurements external brickwork or internal floor area.
Is the left hand flank measure 3010...3700...or 3900.
Ground floor storey height. FFL to Ceiling.
Depth of existing joists.
Measurement from top of flat roof to underside of first floor window sill.
Can then work out pitch, timber sizes, etc etc.
Regards oldun

 

[beezo]

If you are doing this for your old mum. we can answer any question you throw at us, however we need the following information.
Width of gap between your extension and next doors. 265mm

Are your measurements external brickwork or internal floor area. External brickwork

Is the left hand flank measure 3010...3700...or 3900. 3.7m

Ground floor storey height. FFL to Ceiling. 2.6m

Depth of existing joists. 6inch

Measurement from top of flat roof to underside of first floor window sill. 0.5m
Can then work out pitch, timber sizes, etc etc.
Regards oldun

Hope that's everything you need

 

[theoldun]

Depth of extension 3700, assume cavity wall is 300, so less external skin, cavity and 50 mm ledger plate = 250 = 3450, for half run.
Your true rise is 500 above existing roof to under side of first floor window sill less minimum of 150 for flashing = true rise of 350 therefore your true hypotenuse will be 3468 and pitch will be 5,8 degrees. Which will get even worse when you work out actual hypotenuse and rise.
Reason your storey height is 200mm higher than normal and first floor windows are lower than normal.
There are a couple of alternatives, but with respect we feel that they would be beyond you as DIY.
Sorry to you and old mum.
Regards oldun
PS Your present joists at 400 centres are right on border line.

 

[theoldun]

Sorry posted twice.

 

[beezo]

Any idea what the tiles are on the main roof of the house

 

[theoldun]

Our old eyes are well past there sell by date and your photo is far from being very clear, but would say that are a Pantile, possibly Redlands, or could even be Marley Anglia.Hard to tell but minimum pitch will be 17.5 degree with 100mm head lap..
If you have very deep pockets, then there are a couple of ways to design the roof
but whether you could find somebody to construct it, is another ball game.
Regards oldun