ᐅ Span of a Cantilevered Timber Frame Ceiling

Created on: 13 Feb 2024 12:01
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abc12345
Hello everyone,

First of all: I am not looking for a structural calculation or anything like that, but rather have a question about the general construction.

I want to build a pool house in the garden, measuring 6m (20 feet) long and 4m (13 feet) wide. The construction will be timber frame. Ideally, I would like to avoid any obstructive walls or supports facing the garden side, and the roof should not rest on anything there either. Now I am wondering how I should best design or build the roof structure so that the project is practical and functional. Maybe some of you have drawings, plans, or cross-sections showing what such a construction looks like in practice. I have already searched online without much success and hope for your help.

Or do the roof beams actually only rest on the two shorter wall sections and are then connected at the front, on the cantilevered edge, by tenons or metal joist hangers?

I hope it is clear what I mean.

Example photos showing how I imagine the construction are attached.

Open modern garage with white interior, long dining table and chairs.


Covered wooden pavilion with open lounge, sofa, table and lighting.


Thank you very much.
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hanghaus2023
20 Feb 2024 11:30
What is supposed to go into room 1 with a width of 79cm (31 inches)? In my opinion, the short wall should be at least 1m (3 feet) longer. Is the roof, like that one beam, supposed to overhang? I find it hard to imagine such a roof being torsion-resistant if made of wood. Your example pictures both show much smaller overhangs. Have a structural engineer design and calculate this for you. Using a slim steel column will make things much easier.
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abc12345
20 Feb 2024 12:36
This is just a space for chair cushions and all the stuff lying around in the garden... so it doesn’t need to be bigger.

No, the roof will be flush, matching the width of the drip edge. The overhanging beam there will have a swing attached.

Yes, I know that with a suitable support it would be much simpler, but that would bother me visually because then you wouldn’t have an unobstructed view of the garden, but instead would see the support directly.
Nida35a20 Feb 2024 12:48
If I also read about a swing (against the wall?), photovoltaic panels, and walking on top for installation.
In my case, it would be a wooden structure made of beams at least 12cm x 12cm (5 inches x 5 inches).
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abc12345
20 Feb 2024 12:53
Swing was a bit inaccurately described. I mean a hanging swing chair.

There’s nothing wrong with 12cm x 12cm (5 inches x 5 inches) beams. For me, it’s basically about the ideal construction. How thick the beams end up being later doesn’t really matter as long as the structure is sound.
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hanghaus2023
20 Feb 2024 13:07
Nida35a schrieb:

For me, it would be a timber structure made of at least 12x12cm (5x5 inches) beams

For me, it's more like 20x10cm (8x4 inches) due to snow, wind, greenery, and photovoltaic panels—not to be underestimated. The cantilever on the short wall would probably be laminated veneer lumber (LVL) 30x10cm (12x4 inches). How the uplift forces will be transferred into the ground will be very interesting.

Please share the engineer’s report here.