Frankenjoists

[jamesd256]

Hi,

I am planning a shed/workshop floor from recycled wood (me again).

I have quite a lot of 3m 4x4 lengths for the skids (10 or so, although I only need 2 for the plans). The skids will sit on concrete blocks so as to not touch the ground.

I'm working from plans for a 10x8 building which call for a 2x6 joist, but I don't have any of that. I do have hundreds of meters of stock from 2x3 to 2x4, so I'm wondering if there's a solution.

With the abundance of skids available, I can obviously reduce the centre width for the joists, but I am also wondering if I can screw/bolt and glue from the stock I have to get a stronger joist.

I once read that PVA is as strong as the wood itself in many cases, so I'm sounding it out! (2 x (2x4)) + PVA = 2 x 8? I'm guessing not, but I'll be interested to hear the thoughts of all the veterans. Tin hat on.

Thanks for reading,

J

 

[freddiemercurystwin]

If stock is plentiful why not just use more 2X4's at closer centres than you were going to use with the 6X2's?

 

[jamesd256]

If stock is plentiful why not just use more 2X4's at closer centres than you were going to use with the 6X2's?

Thanks for the reply.

That's what I meant by "I can obviously reduce the centre width for the joists", but I guess I didn't make it clear.

I am not experienced enough to know whether using double the number of 2x4's is as effective as the prescribed number of 2x6's, but your comment suggests it is. Easier than glueing!

 

[gregers]

wont bolting 2 together work the same way,leave the centres the same??
i:e making them 4x4

 

[jamesd256]

wont bolting 2 together work the same way,leave the centres the same??
i:e making them 4x4

No idea! To me, it seems likely that that would have less vertical rigidity than a 2x6, but that's the mystery.

Any structural engineers?

 

[ladylola]

As it's the floor you could also just add more concrete supports to take out any flex, and don't forget a dpc between concrete and floor.
For what it's worth I've formed larger timbers by fixing two together so the principal is sound, but I've normally put in mechanical fixings rather than just rely on glue for structural purposes.

 

[jamesd256]

As it's the floor you could also just add more concrete supports to take out any flex, and don't forget a dpc between concrete and floor.
For what it's worth I've formed larger timbers by fixing two together so the principal is sound, but I've normally put in mechanical fixings rather than just rely on glue for structural purposes.

Thanks for the reply!

Good advice about the DPC, will be heeded for sure. In fact I'll be putting a sheet down under the concrete blocks too. Double glazed DPC.

Don't forget the joists aren't on the concrete, they are on the 4x4 skids, which are to spec, and I have more than I need of these, what you're really saying is add more skids for more rigidity in the joists.

I think I'll just double up on the joists with 4x2's, as these are the most plentiful.

Thanks for all the thoughts.

 

[foxhole]

If you want to recycle you could use pallets for base , they are given away free and are hardwood so resist rotting longer.
Why 6 x2? excessive unless you plan on dancing on the roof?

 

[jamesd256]

If you want to recycle you could use pallets for base , they are given away free and are hardwood so resist rotting longer.
Why 6 x2? excessive unless you plan on dancing on the roof?

Thanks for the reply. I take your point. I'm just working to a pre-existing plan.

Mind you, it will be a workshop, and it will have a drill press, a heavy bench, a lathe, a table saw and lots more in there, so I'd rather be safe than sorry given the abundance of stock I have.

Incidentally, the stock comes from long (2.5 - 3m) pallets used to ship metal. Some is hardwood some is softwood. I'm hoping that having no wood in touch with the ground and a good plan for water treatment will keep rotting at bay, but I am making everything modular so as to allow for spot repairs.