New workshop

[mickthetree]

Morning all

The ground has been cleared and hardcore in and compacted.

I am going for 4800mm x 6700mm. With 100mm wall thickness this will give 29.9 square meter which is just below the 30 allowed within permitted development. The building is over 2m from any boundary so the ridge height can be max of 4m

This is the general construction idea so far. I would like to get a small area at the front upstairs for some storage, but the rest I plan of raising the joists to collar ties instead. Although the idea of having a ceiling with insulation and a ventilated roof space for storage is appealing.

Lots of inspiration from Mikes shed guide and others.

Questions:

1.) In this sketchup model I have the roof timbers as 100mm x 50mm (2"x4") Should these really be 150mm x 50mm? (6"x2")

2.) If I cannot get hold of a Paslode, what would be the correct type of nails to use? Galvanised? Bright? 100mm, 125mm, 150mm.

 

[skipdiver]

Maximum span for 4"x2" is around 1.8mts give or take, depending on the roof pitch and spacing, so you would need to use something beefier. Your workshop is the same size as my old one at my last house, just inside the permitted limit and it's a great space to work with.

If you cannot get a Paslode, i'd go with galvanised 100mm nails or possibly screws if you have a decent impact driver.

I left my roof open for storage and you can get a lot in there. Put plenty of hangers in to stop the braces sagging.

 

[RobinBHM]

common rafters:

47 x 150 30-45 pitch 400 c/c maximum span is 3.13M
Of course all depends on roof finish, whether you have purlins etc.

If it was me, I would screw all the framework together

 

[n0legs]

According to my book by CMH Barritt, The Building Acts and Regulations Applied (houses and flats) circa 1992

SC3 approx C16 grade timber:-
Pitch 30-45*
Load of .5-.75Kn/m2

47 x 100 spacing of 400mm clear span length 2.45M
---------------------- 450mm ------------------ 2.38
---------------------- 600mm ------------------- 2.17M


SC4 approx C24 grade timber:-
Pitch 30-45*
Load of .5-.75Kn/m2

47 x 100 spacing of 400mm clear span length 2.58M
--------------------- 450mm ------------------- 2.48M
--------------------- 600mm ------------------- 2.25M



SC3 approx C16 grade timber:-
Pitch 30-45*
Load of .5-.75Kn/m2

47 x 150 spacing of 400mm clear span length 3.69M
-----------------------450mm ------------------- 3.55M
-----------------------600mm --------------------3.23M


SC4 approx C24 grade timber:-
Pitch 30-45*
Load of .5-.75Kn/m2

47 x 150 spacing of 400mm clear span length 3.83M
---------------------- 450mm ------------------- 3.69M
--------------------- 600mm --------------------3.36M

Based on table A13 of Approved Document A1/2

 

[mickthetree]

Wow! that great info! I had planned on 600 centres on the walls and roof with the rafters in line with the wall studs. So C16 2"x6" rafters. The length of the rafters will be 2.8m at a 35 degree pitch.

I had planned the joists to be 4.8m (wall plate to wall plate) so I could use the space above for storage, but it sounds like that isn't beefy enough.

I could raise the joists to collar ties and have less storage space and more head height. Might make for a better space too.

 

[skipdiver]

I did my rafters at 600 centres so it was easier to access the roof space for getting stuff in and out. Did my wallplate at 2.4 mts high and put joists right across from side to side with hangers to the rafters. I used 6x2 for the rafters and 4x2 for the joists because i had a load of it to hand and building regs were not involved. If you put your rafters at 600 centres, then you need 1"x2" roofing laths, assuming you are tiling it.

 

[mickthetree]

Cheers Steve
I had planned on using 18mm osb on teh outside of the roof with felt over top.
I had planned my wall plate at 2.1m then collar ties at 2.5 from the floor. Did you leave a gap so you could get long stuff between the joists? or board on top?
I'm not sure wat hangers are from the rafters. I'll have to look that up.

 

[skipdiver]

Hangers are just pieces of timber fixed from the ridge to the joist to stop it sagging and add strength. I put a small door in the gable end for sliding long timbers in and out of the roofspace and boarded parts of it for storage of smaller items.

 

[mickthetree]

ah! I had thought about putting in a hatch. Great minds ;-)

Did you hang you lighting off the joists then? I've also had it suggested I put the sockets up high to stop cables dragging over the floor.

 

[Adam9453]

it depends what you are planning on making but I think you'll find 2.1 metres internal ceiling height very annoying, you'll constantly be banging things against it if you use 2.4 metre + length board or timbers.
I'd raise the collar ties up as high as possible to give more clear headroom.
with the size space you'll have you could easily have storage/timber racking on the wall at one end without compromising the use much at all. Plus a lot easier to access than up in the rafters IMO.
Having said that i'm sure like all of us, no matter how big the space is, you'll always reach a point where you wish you had just another half a metre lol

 

[skipdiver]

ah! I had thought about putting in a hatch. Great minds ;-)

Did you hang you lighting off the joists then? I've also had it suggested I put the sockets up high to stop cables dragging over the floor.

Yeah, i put flourescents directly onto the joists and this turned out to be a mistake as i was forever smacking them with bits of wood. My current workshop is only half the size and the ceiling height is 2.1, with a small area at the front 2.5. It was a compromise between being able to stand up sheets at the front of the shop and having roof storage space at the back of the shop, so i did about a third with collars at 2.5 and the rest with joists on the wallplate. It's a pain to be honest and i'm forever having to move stuff around but it's what i've got and it'll have to do. If i was doing one your size again, i think i'd do what Adam says and raise the ceiling height to 2.7 or more. You'll have less roof storage but could build a nice timber rack somewhere and still have a bit of roof space. Unless you are building a massive workshop, there will always be compromises somewhere and you have to decide exactly what you can live with and what you intend on doing. When i did mine, i was working as a joiner/builder and it had to double up as storage for building gear, planks, ladders, buckets of tools and all manner of things.

As for the sockets, you can never have too many and a mix of wall ones and a few at height around the ceiling is a good plan.

 

[davem62]

Hi Mick
Have just replaced my flat roof with a pitch, all the roof was screwed using joining plates from toolstation, and covered with 11mm osb then cover with membrane and slate effect tin sheet sourced off the bay, although dearer than felt once done its forgotten. If you use felt you'll be doing it again sometime in the future and would always be better done hot rolled not with felt nails

Regards David

 

[mickthetree]

That does sound goo David. I may well have to felt the roof for now then look for a better option in a years time (spread the cost).

I just called the company I am buying all of the timber from and I'm clearly new to this game. I have a quote from them for the exact lengths I require, but it seems they get this in from a timber supplier cut ready to my lengths. Otherwise they will just supply what I need from 4.8m lengths and I have to get out of it what I want. How the heck does that work? Does this mean I end up with loads of off cuts? If so I could order less and see what off cuts I get and maybe save some money? Can anyone explain to me the dark art of dealing with a timbver supplier?

 

[Fitzroy]

I assumed that you could only really buy from a set of 'standard lengths', my local timber yard had standard lengths for C16 regularised treated ex 100 x 40, so actually 95x47. Their standard lengths were: 3.0m, 3.6m, 4.8m and 6.0m. The cost per meter increased marginally with the longer lengths. I used sketchup to work out all a full cutting list and then worked out a semi optimised list of standard lengths to minimise my waste. ie:
- My wall studs are 2.7m on the front and 2.4m on the back wall. so I ordered 4.8m lenghts to do the back wall (cut in half) and 3.6m lenghts for the front wall, the 0.9m off-cut from each was cut in half and used as noggins in my floor as the joists were on a 400mm spacing.
- There are a bunch of other shorter lengths you'll need for jack studs and cripple studs around windows and doors, noggins, etc. Many of your off-cuts can be used for these, just keep them stacked in a way they are use-able.

In my mind wood is not cut to bespoke lengths so there will always be waste cuts, i assumed if I gave the wood-yard my cutting list they would not be particularly efficient in selecting what to cut and they would keep all the offcuts.

No idea if this is how it should be done, but that's what I did. I've ended up with relatively little waste however I did have to get the yard to drop off and extra 3.6x150x50 and sheet of extra OSB. Better an extra £10 for the extra delivery than having meters of spare wood left.

F.

 

[RobinBHM]

Generally I find it best to ring the supplier first to find out what lengths they have (which may vary from time to time depending what pack lengths they have in the yard at the time) and then work out what the best lengths to order to cover. The merchants wont be that interested in working out the most efficient way to do it, they want it easy, so will want a simple tally ie 100 x 50mm section: 10/5.4, 20/3.6 etc

Construction softwood, like studwork and joists etc usually is available in: 2.4, 3.0, 3.6, 4.8, 5.4, 6.0

I would also check what the finished size the timber will be as some suppliers have a finished section that is quite mean (Im not a fan of CLS as it is so small generally, even if it cheap)

Some suppliers that do eased edge studwork will make sure it is all the same section, so you know it will all be say 95 x 47 not some 45 or 43....

 

[mickthetree]

Cheers chaps, I think I'll give them a buzz in the morning and see if they can explain how they work it. Its not far from where I work so I could pop in.