ᐅ Building a garden shed yourself (frame dimensions) – Is 8x8 timber beam a good choice?

Hello everyone,

We would like to build a garden shed.
It should be used both by our son for playing and by my wife as a sewing room.

I planned to construct it as a timber frame.
The exterior cladding would be done with tongue and groove profile boards.
Inside, I would like to cover the walls with OSB panels.
The space between the profile boards and OSB would then be insulated with suitable material.
This way, it would be comfortable to use even at somewhat cooler temperatures.

A friend has offered us squared timber measuring 8 x 10cm (3 x 4 inches).

Now I wanted to ask if you think 8 x 10cm (3 x 4 inches) beams would be sufficient for the frame.
I would place the studs at a distance of 60cm (24 inches) apart.

Thanks and regards

Thomas

Either you go by intuition, which will probably work depending on the roof area and the load on it.

Or you calculate it. Vertical snow load in kg/sqm (kilograms per square meter) on the roof surface plus the weight of the walls and roof structure itself, then divided by the number of studs, wood species, and cross-section. There are datasheets available for the load-bearing capacity of a stud in the vertical direction. Wind load is absorbed by diagonals in the stud frame. Include a safety margin. Such a calculation is by no means complete or absolutely accurate, but for small self-build projects with modest requirements, it at least provides a reference point.

Hi,

thanks for your reply.
I hadn’t really thought of that yet... :-(

I’ve now roughly calculated everything. I took the roof rafters, wood, roofing material, and snow load into account, rounded up a bit, and ended up with about 2,000 kg (4,400 lbs).

I couldn’t find any direct information about the wood’s load capacity.

KVH (structural laminated timber) 60 x 100 mm (2.4 x 4 inches) can hold 790 kg (1,740 lbs) over a length of 2.5 m (8.2 ft).

So, I’d say that from a calculation standpoint, it should be okay.

I would have about 22 support posts to carry the weight.

Even if you assume a load of 3,000 kg (6,600 lbs) due to sheathing, insulation, or other factors, that would still be only 136 kg (300 lbs) per post.

Best regards

Thomas

Take a look using the search terms DDR garden shed type GL 10 / 12 / 14 / 17 / 19 (the numbers indicate the size in square meters), they are fairly well documented online.

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As you already pointed out, the roof structure needs more attention. Regarding the beam thickness, I have no concerns for the side walls. In the US, two-story houses are built using 2"x4" beams, which are the equivalent of long-hole bricks, calcium silicate bricks, or aerated concrete blocks in other regions.

If the entire structure is meant to be walkable, 100 by 60 mm (4 by 2.4 inches) pine beams spaced 60 cm (24 inches) apart with a 2.5 m (8.2 ft) span will not be sufficient.
Walkable roofs or terraces are calculated with a live load of 400 kg/m² (82.0 psf). Your current setup results in about 150 kg/m² (31 psf), including the dead load of the roof.
To support 400 kg/m² (82.0 psf), you would need beams sized 14 by 8 cm (5.5 by 3.1 inches). The roof with the thinner beams will still hold up well against climbing children, but I would not recommend building a roof terrace on it.