Shed Self Build- timber runners

Tr1ckieD1ckie · 14-05-2021 12:34pm #1

Hi folks,

Starting my shed build this weekend. Building a timber framed shed approx 3.6m by 4.8m.
Book I'm working off (Sally Coulthards) recommends using 4*4 treated runners on top of concrete blocks which is broadly the approach I'm taking.

I couldn't source treated 4*4s (except short ones used for decking) so I'm going with pairs of 6*2 treated bound together.

Looking for suggestions on whether to use them vertically or horizontally).

Also what's best to bind them together- bolts/ screws/nails?

Grateful for any advice here
Best
TD

Calahonda52 · 14-05-2021 3:22pm

6 by 2 massive over kill
Have you priced timber these days..
Anyway, what spacing are the blocks?

4 by 2 with well fitted noggins will go a long way
can you post a scan of what her shed looks like

The Continental Op · 14-05-2021 3:52pm

I lay the bottom layer of shed timber on a layer of DPC, seems to make it last a bit longer, but being treated and soaking the contact areas in Protim 265 probably helps.

6x2 is more of a thick plank, I use treated 3 x 2 nominal which is about 2 3/4 x 1 5/8 two of those side by side would be more than enough, depending on spacing obviously.

Tr1ckieD1ckie · 15-05-2021 11:22am

Many thanks folks- I will try and scan the plan from the book when I get a chance.

Pending this, just to clarify I'm talking about using the pairs of treated 6x2s as timber bearers which sit on top of the concrete blocks and the plastic DPC. (I've already bought the 6x2s.)
Then I'm building the floor frame as per the book out of treated 4x2s- this will sit on top of the treated pairs of 6x2s and the walls and roof frame out of treated 3x2. All nominal measurements.

So the pairs of 6x2s bound together will be almost the size of sleepers (not quite as wide) but in 4.8m lengths for strength and stability- can only seem to find 2.4m sleepers

So any view on whether to use the pairs of 6x2s for timber bearers standing up or on their sides- and would bolting them together with say M12 100mm bolts be ok?

Lumen · 15-05-2021 11:27am

Tr1ckieD1ckie wrote: »

So any view on whether to use the pairs of 6x2s for timber bearers standing up or on their sides- and would bolting them together with say M12 100mm bolts be ok?

1. Strength in depth, so always standing up.
2. M12 is way overkill for sistering joists, but OK. You're not really transferring load between them in this application (assuming they're both full lengths).

listermint · 15-05-2021 3:50pm

4x2 screwed together vertical is enough for this application.

Tr1ckieD1ckie · 15-05-2021 8:32pm

Thanks all, very grateful for the advice and I note that 4x2 would have been enough. As it happens there was only a euro approx difference in cost between the 4x2 and 6x2 and 6x2 looked much more deeply treated

The Continental Op · 15-05-2021 8:40pm

Look at it another way if your block foundations are really good you hardly need those runners at all.

Shed Self Build- timber runners

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