# Rob's New Workshop



## ratkinsonuk (21 Feb 2006)

Here are the plans for my new workshop, 24' x 12' (Click on the link for larger version).

I'd be interested in any comments about whether it looks engineeringly (?) sound or not. I know I need to change the rafters to 2' centres, for instance.

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Cheers, Rob.


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## trevtheturner (21 Feb 2006)

Hi Rob,

That looks good and should make an excellent workshop.

Just one observation on your plans. The door(s) on the front elevation are shown as 4 feet wide. Obviously I don't know exactly what you intend to house in the workshop, but I would consider enlarging the doorway to 6' wide to accommodate a pair of 3' doors. Better to make the opening larger at this stage, rather than discover later on that the doorway is too narrow.

Cheers,

Trev.


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## OLD (21 Feb 2006)

Here is a couple of links you may find usefull 
http://doityourself.com/wall/fwalllayout.htm
http://www.hometime.com/Howto/projects/framing/frame_3.htm

you may want make the openings stronger at windows and d/door depends on roof load. I am building a garden office useing this construction and glueing and nailing sheathing ply on the stud frame to stop it racking .If you use joists so that the roof section is a triangle its the strongest and simplest structure with no side load to walls and provides strong storage, but there are lots of different designs possible.


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## tim (21 Feb 2006)

Rob,

Trev's comment is spot on re doors. You may lose a bit of wall space, but paired doors that are too narrow on their own are a pain.

Can you make it taller inside? Once you have a floor in there you won't be able to stand a sheet of ply on its end except within the middle 4 ft - which is probably where your machines will be in the way. I didn't take floor thickness into account when I built mine and its just too short at the walls to be able to do this - very boring.

Also if your budget stretches to it, add a couple of veluxes or similar - makes a big difference to light and ventilation quality.

Cheers

Tim


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## ratkinsonuk (21 Feb 2006)

Thanks for the info everyone, especially the links OLD. I think I saw that episode of Hometime a few years back.

It's also good to know that the methods I'm using are the correct ones.

If I pinch 6 inches from either side, I should be able to get a 5' double-door in.

The headroom won't be too much of a problem, as the whole thing sits on a concrete slab, and I'm not intending to build a false floor on top, just ply and then lino. The slab will have a plastic membrane under it, so damp shouldn't be a problem. That'll give me close to 8' headroom.

As the trusses will be connected to a ridge-beam, the truss braces can be a lot higher, 12 inches or so from the top. I'm a little worried that this may push the walls out, so there will be top-plate braces in the middle. I'm using felt shingles over OSB to keep the weight down.

There's a string of double-glazed windows along the front (North facing into the garden) and high-level security glass along the back, so there should be plenty of natural light.

If this isn't enough, I can easily retrofit some sky-lights.

Ventilation is a problem, but I think I've found a company that will do ridge vents or at least vents on the top slope.

Still debating heating, but that's a LONG way off yet.

Thanks again, and keep the comments coming.

Rob.


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## les chicken (21 Feb 2006)

Rob

I second the comments on the doors etc. If you build the framework out of 3x2 cls and clad the external with say 9mm or 12mm ply it will make a really solid structure. On the outside use shiplap resulting in a solid draft proof built to last workshop. If you brace the sides to keep them square and upright before fixing the roof trusses 4x2 minimum at 2 feet centres. Once again use ply for the roof fixing down with screws or ringshank nails, use silicon between sheet edges in case of leak through felt. The ply will bring the whole structure solid removing the need for cross bracing resulting in a cathederal style roof.

Some pictures of a summer house I built for a neighbor last year. Dimensions are 20 ft X 16 ft internal.





















Les


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## ratkinsonuk (22 Feb 2006)

Les, thanks for sending the pictures - the place looks very welcoming  

Did you use a ridge beam to hang the trusses from, and if so, what were the dimensions?

Was there any flex?

Rob.


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## tim (22 Feb 2006)

ratkinsonuk":se1j4lxh said:


> The headroom won't be too much of a problem, as the whole thing sits on a concrete slab, and I'm not intending to build a false floor on top, just ply and then lino. The slab will have a plastic membrane under it, so damp shouldn't be a problem. That'll give me close to 8' headroom.



Does that mean that you will have a threshold to negotiate in and out of the doorways? Could be a pain if you want to wheel stuff in and out.

Also re ventilation - that was one of the reasons for getting the veluxes - I leave the trickle vents open all the time and its fine.

Cheers

Tim


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## ratkinsonuk (22 Feb 2006)

I intend to build a ramp up to the doorway, as the floor level will be 6'' or so above ground level, to keep the DPC well above the earth :-






Would I be right in thinking, to get enough veltilation for this area, I'd have to install at least 6 Velox windows? A bit of a pricy option compared to standard roof vents?

Rob.


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## tim (22 Feb 2006)

> Would I be right in thinking, to get enough veltilation for this area, I'd have to install at least 6 Velox windows? A bit of a pricy option compared to standard roof vents?



Only if thats your only source of ventilation and you are subscribing to building reg requirements (which doesn't apply in the same way for temporary structures).

If you are putting in bought dg units then the frames will now have trickle vents as standard anyway.

Cheers

Tim


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## ratkinsonuk (22 Feb 2006)

Certainly my intention to go the DG route. Thinking about it, my recent house extension had to have trickle vents as well.

Do you reckon these would be enough to eradicate condensation and ventilation problems, without having to install roof vents?

Rob.


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## les chicken (22 Feb 2006)

Rob

The ridge beam I used was 6x2 tanalised timber, together with 4x2 roof trusses with birdsmouth for fixing. When the roof had been fixed down and the side stays removed there was no flex or movement whatsoever, the roof easily supported two men laying the felt with no bounce. The walls are also solid.

Building a wooden workshop this way I do not believe you will get condensation as long as there is some ventilation. It will also stay quite warm because of the natural insulation wood will give. 

If I can help in any way just ask, I have built three of similar construction and they are all watertight and snug.

Les


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## ratkinsonuk (23 Feb 2006)

Les, anything you can send over similar to my workshop re. plans, layout, materials, etc. would be brilliant. Also, any idea on overall cost would be really useful.

I'm probably going overkill on the time spent on design, but my take on it is, get it right now and you won't have to spend hours looking at that window that you wished you'd made 6'' bigger :wink: 

This thing's probably got to stand 20 or 30 years, so needs to be right from the start.

Rob.


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## les chicken (23 Feb 2006)

Rob
What are your plans for foundations and floor, congrete floor or padstones and wooden floor ???

Les


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## ratkinsonuk (23 Feb 2006)

6'' concrete slab on top of plastic barrier, on top of sand/gravel, on top of hardcore.

Will level slab with levelling compound, then [email protected] flooring, finally lino or some other cheap flat covering.

Rob.


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## les chicken (23 Feb 2006)

Rob

Would suggest on top of congrete slab, 4x2 tanalised frame work 2ft centres with noggins same spacing. At each joint pack up with slate to allow air flow and level. Then 3/4 external ply gripfix and screw to frame, there will be no problem with expansion and the floor will not move or squeak. Prior to fixing the ply down give it a liberal coating of wood preserver on the bottom and sides and allow to dry.

This will give a good floor and good fixing for the side and end panels mounted on the edge. Allow the ply liners on the sides to overlap the floor by three inches this will prevent water getting into the edge of the floor.

Something to think about.

Les


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## ratkinsonuk (23 Feb 2006)

DaveC was saying similar, but it means I loose a little bit of headroom, and it costs me a bit more time and money.

Apart from a slightly warmer floor, I can't see where the benefit is vs cost.

My assumptions are based on the fact that most modern houses have solid concrete floors.

Although it would be quite a pain, I could strip everything out and lay a false floor afterwards, if there were problems.

I assume there's something at the back of your mind that's saying I'm doing something wrong?

Rob.


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## les chicken (23 Feb 2006)

If you compare the cost of tongue and groove flooring to the frame and ply I do not think there will be much difference.

You are right regarding houses with concrete floors but they do not have wooden outside walls.

Lay the concrete slab level to the ground, with the framework packed on slate it will give airflow under the floor. This will prevent any premature rotting of the wood. The ply with an overlap of three inches still gives 7ft 9ins of wall height. The maximum height you can go with a pitched roof is 4metres without planning permision 12 feet approx with a cathedral style roof as I explained in previous post.

If you check, the most problems with sheds rotting is the floor goes first where water is allowed to rest at the base. This is where airflow under the floor helps an enormous amount.

Les


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## wizer (24 Feb 2006)

les, when you say pack up with slate. How much packing are you talking about? 20mm-ish? or am I on the wrong tracks?


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## les chicken (24 Feb 2006)

Sorry about the delay in replying had a power cut tonight blew the computer out had to find a pub to stay warm and watered.

A single layer of slate whatever thickness at each joint is enough to enable air flow under the floor. If the wood is bowed always lay with the bow upwards so that it can settle.

If you wish to lay the floor on to the concrete base, then make sure the sole plate of each side / end is laid on a strip of DPC which is wrapped up around and stapled to the sole plate. This prevents the water laying against the wooden sides.

If I am not clear ask me again but blame the Electricity supplier for forcing me out. :roll: :roll: 

Les


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## Neomorph (25 Feb 2006)

les chicken":1k5wfn6i said:


> If I am not clear ask me again but blame the Electricity supplier for forcing me out. :roll: :roll:
> 
> Les



.. or the alcohol for blurring your typing  

When you say "blew the computer out" do you mean the computer went bang or just shut off. I lost one PC when we had a power surge followed by a 5 hour blackout. Since then I have fitted surge protectors for every electronic device in my flat but especially for my computers. With them being available everywhere these days it's well worth the outlay.


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## ratkinsonuk (26 Feb 2006)

OK - I've come up with a cunning plan  

By doing away with the concrete floor totally, and adding a 3rd supporting foundation, I should save quite a bit of money and time :-







The question now is, how thick do I need to make the joists to ensure there's no flex over the 6' span? If i put noggins in-between each joist, that will ensure they remain upright and add some stability.

Rob.


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## OLD (26 Feb 2006)

Here is a link for you
http://www.diydoctor.org.uk/projects/load-bearing_walls.htm
how about some insulation between the joists.


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## ratkinsonuk (26 Feb 2006)

Thanks OLD.

Look's like if I went for 600mm (2') centres, I could get away with 5'' x 2'' :-

"47 x 122 mm = 2.09 m"

Anyone know the average cost of 12 lengths of 5'' x 2'' x 12' in pressure treated wood?

Rob.


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## OLD (26 Feb 2006)

Thats a size not stocked by my local wood yard
http://www.fortimber.demon.co.uk/white_wd.htm
Also if you are cladding the wall could rest on the floor joists.


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## les chicken (26 Feb 2006)

Rob 
you could just use concrete blocks on their sides as padstones set on concrete every 2 feet. 6x2 is the standard tanalised size. 

Les


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## bobscarle (27 Feb 2006)

Rob

Just pricing up for my new workshop / shed. I am looking at 4" x 2" pressure treated timber for my floor joists. I was quoted £1.10 + VAT per metre.

Bob Scarle


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## ratkinsonuk (27 Feb 2006)

That's pretty good.

The costs I could find worked out at about £80, where your supplier comes in at around £55 (£1.30 x 43m).

Who are they - it may be worth me buying all the timber from a single 'cheaper' supplier?

Rob.


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## bobscarle (27 Feb 2006)

Rob

I was quoted that price by Edwards in Redditch, part of the Buildbase group. Just had a quick look on their web site, it looks like the closest branch is in Hadleigh, about 11 miles away.

Bob


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