Roofing ideas - potentially low pitched (sloping) roof.

kentech

Hi people! I've recently built an extension.

It's in two sections, making a sort-of 'L' shape. The longer section roof should be a simple pitched roof of 34.11 degrees.

The problem comes when sloping the bathroom's roof from the main house (bungalow).

The problem is, I've worked out that the pitch is around 13.72 degrees and have read that this could seriously limit what tiles I use. I'd like to use the same tiles for the whole extension...

I have attached a plan of the extension, with some scribbles... The thin lines are ridge lines and gulleys. The thick lines show the slope of the roofs. The black lines are existing, The red lines are what I'm thinking of building...

A few questions, if you don't mind:

1. Is 13.72 degrees too low for tiling?

2. Are the limiting factors of tiles purely on their weight when exposed to, say, large amounts of rain or snow? Or is it to do with moisture retention rotting the batons or roofing felt?

3. Given the l-shaped design, could anyone suggest a better roofing option? Ie. pitched roof on both the sections, sloping roof another way, a spire? Perhaps a village bell tower?

thanks people!!

ArchNomad

13.72 is an extremely low pitch for a tiled roof and well below the standard recommended pitch, however there are tile manufacturers that have products designed for low pitched roofs. (Forticrete Centurion for example)
There are specific fixing and lapping details must be adhered to. Technical depts. should be consulted prior to use.

Other options are low pitch roofing materials like zinc or a a profile roofing sheet like Nordman or there's always the flat roof option.

kentech

ArchNomad wrote: »

(Forticrete Centurion for example)
There are specific fixing and lapping details must be adhered to. Technical depts. should be consulted prior to use.

I had a look at this. All seems a little over-kill, and again this is why I asked the question about moisture retention? Surely if I've proper ventilation is present, and the roof is overspec'd for load-baring - perhaps build with 8x2s rather than 5x2, any tiles will suffice?

muffler

kentech wrote: »

I had a look at this. All seems a little over-kill, and again this is why I asked the question about moisture retention? Surely if I've proper ventilation is present, and the roof is overspec'd for load-baring - perhaps build with 8x2s rather than 5x2, any tiles will suffice?

Have you factored wind driven rain into the equation?

muffler

Just another thought. Is there any reason why you cant have the bathroom/kitchen/dining under the one roof?

kentech

muffler wrote: »

Just another thought. Is there any reason why you cant have the bathroom/kitchen/dining under the one roof?

I don't think this is feasible - did you see the image? How would you propose to do a single roof on an L-shape construction? Or have I misunderstood?

muffler

kentech wrote: »

I don't think this is feasible - did you see the image? How would you propose to do a single roof on an L-shape construction? Or have I misunderstood?

There's a room to the left of the bathroom which has an apex roof over it it appears. I assume the bathroom and kitchen/dining are proposed so why not re-centre the ridge over the wall between the bathroom/dining room (aaprox.) and have a valley connecting with the bottom of the valley of the roof over the room to the left. The remainder of the roof projecting out with the kitchen would be near enough mono pitched.

Its difficult to fully understand without the full floor plans and elevations showing what's existing and what's proposed.

kentech

muffler wrote: »

There's a room to the left of the bathroom which has an apex roof over it it appears. I assume the bathroom and kitchen/dining are proposed so why not re-centre the ridge over the wall between the bathroom/dining room (aaprox.) and have a valley connecting with the bottom of the valley of the roof over the room to the left. The remainder of the roof projecting out with the kitchen would be near enough mono pitched.

See attachment - I may have misunderstood?

muffler wrote: »

Its difficult to fully understand without the full floor plans and elevations showing what's existing and what's proposed.

Very true. There are no plans except for what you've seen

Edit: I think I did misunderstand - check image #2

What to do with the rest of the roof? This is a single-story construction, and as I understand it the block work cannot exceed the height of the original house's walls? So, the roof over the kitchen would be at what pitch?

muffler

No. 2 is roughly what I would have in mind. Care needs to be paid to flashing the junction of the 2 roofs where they meet (left side of bathroom) as you effectively have a flat channel at that point. The remaining roof over the kitchen could have a ridge centred over the middle of the kitchen (approx.)

In saying all that I am mindful of the forum charter which prohibits us from offering any type of design service so Im merely firing suggestions here to help you out.

kentech

muffler wrote: »

No. 2 is roughly what I would have in mind. Care needs to be paid to flashing the junction of the 2 roofs where they meet (left side of bathroom) as you effectively have a flat channel at that point. The remaining roof over the kitchen could have a ridge centred over the middle of the kitchen (approx.)

In saying all that I am mindful of the forum charter which prohibits us from offering any type of design service so Im merely firing suggestions here to help you out.

And I'm much obliged of your suggestions - Keep firing!

I like your idea, but I cannot see a nice way of joining the kitchen roof with the shallower slope of the dining roof. I guess it's because I simply don't know what techniques are used on vertical sections of roofs when they join.. I guess something like a soffit, and then a standard timber wall?

Hmm..

muffler

kentech wrote: »

And I'm much obliged of your suggestions - Keep firing!

I like your idea, but I cannot see a nice way of joining the kitchen roof with the shallower slope of the dining roof. I guess it's because I simply don't know what techniques are used on vertical sections of roofs when they join.. I guess something like a soffit, and then a standard timber wall?

Hmm..

If you can imagine putting a new apex roof over the kitchen and linking it to the roof over the dining area you will have a continuous roof along the right hand side (as viewed on plan), ridge in the middle obviously and then a sloped roof to the left of the ridge. This as you say will need to be butted to a wall structure that needs constructed in a straight line with the rear wall of the bathroom and extending over the kitchen/dining area. Alternatively you could build up the wall to the left of the kitchen where it projects out and have a mono pitched roof to the right.

If you are unsure of all this you should engage a local architectural technician who will get you sorted.