Minimum angle for a lean-to on a rear house extension

soc$

Could someone tell me what the minimum angle is for a lean-to roof on a rear house extension? I'm trying to roughly work out in my head if it's possible to do a lean-to given how far out I'd like to go and how high the upstairs windows are currenlty located -

Thanks in advance

sinnerboy

Some concrete tiles will allow you go as low at 13 degrees.

soc$

sinnerboy wrote: »

Some concrete tiles will allow you go as low at 13 degrees.

Thanks

martinn123

soc$ wrote: »

Could someone tell me what the minimum angle is for a lean-to roof on a rear house extension? I'm trying to roughly work out in my head if it's possible to do a lean-to given how far out I'd like to go and how high the upstairs windows are currenlty located -

Thanks in advance

The minimum angle is 0 deg, which would be a flat roof, you will get plenty of advice here as to the suitability of a flat roof.
Alternatively depending on the width of the extention you might consider a roof where the roof joins the house in a inverted V shape, the wider the extention the more height you need. Measure the height you have to the upstairs window and post the width, and I may be able to advise.

soc$

martinn123 wrote: »

The minimum angle is 0 deg, which would be a flat roof, you will get plenty of advice here as to the suitability of a flat roof.
Alternatively depending on the width of the extention you might consider a roof where the roof joins the house in a inverted V shape, the wider the extention the more height you need. Measure the height you have to the upstairs window and post the width, and I may be able to advise.

Thanks - I know we could do a flat roof and had thought about a gable style roof but in our minds we really wanted a lean-to to maximise light however I suspect we would have to compromise on how far we come out at the back. I don't have the height of the upstairs window to hand but I know we'd like to come out around 3.5 metres at the back and my gut feeling is a lean to might not be possible.

The garden is north facing and we plan to have an open plan dining sitting room so we'd like to maximise light in from the back garden.

I'll dig out the height of the windows and post it anyway.

In the meantime I guess I should do a search for flat roofs and how to maximise light

DOCARCH

If you are looking for light in a lean-to roof, just bear in mind that the minimum pitch Velux recomend is 15 degrees, anything less and they are likely to or may leak. This might influence your decision?

Velux do a special housing to use standard sized Velux roof windows for flat roofs (Velux FRS), so with a flat roof there is plenty of opportunity to get light in.

Most concrete roof tiles can be used down to 17.5 degrees once specific technical advice from the manufcaturer is adhered to (and also depending on location and exposure). There is only one particular concrete roof tile (Centurion) that can be used down to 12.5 degrees, so you might be pretty limited if considering anything lower than 17.5 degrees.

I have seen concrete tiled roofs done at 12.5 degrees and quite frankly they look a little stupid as the pitch is so low!

soc$

Thanks for the advice guys - I think we might go with a flat roof so we can maximise the interior space so now we need to consider our options for maximising light.

sydthebeat

soc$ wrote: »

Thanks for the advice guys - I think we might go with a flat roof so we can maximise the interior space so now we need to consider our options for maximising light.

coxdome or atrium rooflights are a great addition....

also with your flat roof, you can increase your floor to ceiling height to add a sense of proportion..

muffler

martinn123 wrote: »

The minimum angle is 0 deg, which would be a flat roof

How would the rainwater run off?

slavetothegrind

There is also tile effect roofing like nordman and kingspan, good down to 4 degrees!


....now that i've insulted the architects here i'm off!!:D

soc$

Thanks for the replies everyone.

We're gonna go with a flat roof and use some large pyramid style rooflights (or maybe just one really big gable style one).

It was the last big choice for the renovations which is cool - now the fun/frustrating bit starts - deciding on the interior finishing

RKQ

DOCARCH wrote: »

I have seen concrete tiled roofs done at 12.5 degrees and quite frankly they look a little stupid as the pitch is so low!

I'd agree 100%. Once you go below 20 degrees you should consider a flat roof. A flat roof might aid fire escape from the bedrooms in the event of fire!
Don't place your dome or pyramid rooflights directly under the rear windows - don't want to jump out the window only to fall thru the rooflight.

antiskeptic

muffler wrote: »

How would the rainwater run off?

Perhaps a solar powered pump - with intake point positioned in the puddles?

muffler

antiskeptic wrote: »

Perhaps a solar powered pump - with intake point positioned in the puddles?

soc$

RKQ wrote: »

Don't place your dome or pyramid rooflights directly under the rear windows - don't want to jump out the window only to fall thru the rooflight.

:rolleyes::D

padjocollins

anyone got a link to kingspans roofing tiles, my roof is going to be 10 degrees and i just found out i can't go with normal concrete tiles ... long story. thanks

BryanF

No grave digging.