BucksDad Workshop Build

[BucksDad]

So even though I've been thinking about a workshop for most of 2021, nothing has happened with this yet as we've had other priorities, however we are having the garden landscaped soon so the workshop planning is starting up again.

So, the plan is to build a 3m x 3m workshop on a concrete base with 2 course bricks with a flat roof and everything under 2.5m. One single door on one side and an 800 x 450 window on another.

The plan is to make it look garden office and be an easy conversion to an office space so that if we do sell, it's another tick in the box for prospective buyers.

I have worked out the costings below and used various online calculators to get to these figures. My brain just does not seem to get on with 3d modelling programs to actually draw this out. The costings below don't include the base / bricks as that is already covered by the garden landscaping costing.

Let me know what you think of the costings, anything I've missed and any value engineering ideas! Prices are a combination of local timber yard and wherever is cheapest locally (e.g. Wickes for OSB)

- 4 x 2 Studwork - 4.2m lengths x 35 - £12.60 each - total £441
- 47 x 150 x 3.6m joists - 14 - £16.2 each - £226
- 25 x 38 x 3.6m battening - £200
- Firring strips - 9 - £10 each - £90
- OSB T&G 18mm roof sheets - 10 - £26 each - £260
- 90mm PIR insulation - 14 - £45 each - £630
- OSB 11mm 8 x 4 for walls - 12 - £29 each - £348
- Plasterboard 12.5mm walls - 12 - £10 each - £120
- Plasterboard 12.5mm ceiling - 3 - £10 each - £30
- Tyvek Housewrap - 1 - £115
- Iro Cladding (2 sides) - 8 pack 5 of - £195 each - £975
- Box Profile Cladding (2 sides ) - £200
- EPDM Roof - £480
- Vinyl Flooring Tiles - £230
- UPVC Window - £120
- Solid Core Door (will be clad with Iro Timber) + fixings - £175

That comes to a total of £4655. Added on 15% for contingency / fixings etc gives a total of £5350

The obvious saving would be cheaper cladding for the 2 visible sides, but I really like the Iro look, as does the design committee.

I'm also allowing £1000 for provision of electrics.

I'm also going to have to get someone to build this for me. I have built 2 'sheds on wheels' for the side of my house (will put a build thread up sometime soon when they're finished) and it has taken me so long with so many mistakes - as would be expected for my first attempt at anything like that. The design committee doesn't have the trust / patience for me to do it and realistically, I don't think I have the time / skills / tools either and being a small(ish) garden with nowhere to hide it, I want it to look nice.

So I'm also going to allow for 10 days at £250 / day for a joiner/carpenter to build it (or as much as they will for 10 days, I'd hope 10 days would mean at least it would be watertight, door and window fitted. I figured I can do some of the internals).

Anyway, that means the entire cost comes to:-

Materials - £5350
Electrician + Electrics - £1000
Labour - £2500

Grand Total - £8850

This is an expensive hobby!!

 

[Fitzroy]

Some thoughts.

3mx3m is not very big, but it may be all you have space for. Also watch out are you talking external or internal. I built a shed 5yrs back now (gosh) and was planning on 3m x 6m, internally it's 2.7m x 5.7m, and the 2.7m is just too narrow for two outer worktops and a central bench. With clad walls and insulaution and linings you lose a good bit.

EPDM roof looks expensive. I recently did my outhouse roof at 3.1x3.8m and it was £250 for rubber, adhesive, edging etc from www.permaroofstore.co.uk

You have no cost for screws/nails. If you are screw fixing your cladding with visible screws I'd suggest stainless. Probs looking at £100-£150 for all your needs, so could be in your contingency.

Electrics are my bane, I still run an extension lead out to mine! I'm 70m of run lenght from the consumer unit at the front of the house to the shed so I need a local earth spike blah blah. I was quoted £2k a few years back for a 10mm2 connection.

Timber costs have really soared so probs not a great direct comparison, but my build costs are here WIP: 6mx3m Pent Workshop build: Exterior Done!. Ignore the electrics estimate (it was wishful thinking).

There are cheaper alternatives to Tyvec, likely save you £50.

It looks like you have an aweful lot of timber for a 3x3 shed.
- You have 200 meters of stud and joists, I used 300m in my 3mx6m build
- 12 OSB sheets will cover 35m2 of wall, you only have 28m2 on a 3x3x2.4m shed. Also not sure what you are using the OSB for as you have plasterboard for the internal linings. With a clad shed you don't need anything on the outside, it's insulated studwork, house wrap, battens then cladding. Adding an OSB layer becomes a condensation risk
- The surface for the EPDM doesn't need to be T&G, just 18mm osb or plywood will be fine (plywood was cheaper on my recent roof than OSB). Should save you a bit against that £260

Having someone else build it to your spec and with your materials will need careful control and lots of work upfront to find the right person. You'll have folks sat around waiting for you to say how to do something if it's not crystal clear.

Fitz.

 

[Jameshow]

Why 10 roofing sheets surely 3 1/2 should cover the roof?

Also 14 6x2 I would have thought 6 on 2ft centres plus 2 each end = 8??? Even 16" centers would be 11?

Looks good otherwise.

Cheers James

 

[martin.pearson]

How far & when are you planning the electrics? If your getting the garden landscaped then you might want to include any trenching work with that if you haven't already.

 

[BucksDad]

Thanks for all the comments.

Very nice build you have there Fitzroy. The fact it took you a year and you look very competent is exactly the worry I would have if I did it myself

Dimensions
Yes I am aiming for 3 x 3m internal finished dimensions. The actual size of the pad will be 3260 x 3260mm. This will allow for 100mm for the brick base (cladding will overhang) and 30mm internal for OSB + plasterboard. My garden area is approx 20m x 15m so I don't have room for anything bigger without encroaching on the space for the kids.

Studwork
The studwork calculation was done with 400 centres with a stud height of 1981 with a calculation of :-

2500mm height

Roof - 2mm EPDM roof. 18mm OSB. 50mm firring. 145mm Joists. Total roof of 215mm
Base - 50mm concrete (above ground) + 160mm brickwork = 210mm base

Remaining height for timber frame = 2075mm. Minus 47mm top plate & 47mm bottom plate = 1981 stud height

Wall Framing Calculator with Stud Spacing Diagram Metric (blocklayer.com) The calculator allowed for all the studs plus 3 plates - top, bottom and noggins. That works out to 122 linear metres. I added on a few extra lengths for extra stud work around doors and window.

Roof Joists

Has to be 400mm centres with that size of joist. Extra lengths allowed to have a 10cm overhang on each side

Screws / Nails - Sorry I should have said. The 15% contigency was to include screws / nails etc.

OSB Wall

Yes sorry I worked on 3 sheets per wall but forgot the 3rd sheet would have wastage which could be used on the next one. As you say, could come down by a couple of sheets probably. The plan was to put OSB + plasterboard inside - one to deaden sound and two to make it really easy to fix stuff and not faff about with plasterboard fixings but maybe it's overkill and I should dump the OSB.

Roof sheets - @Jameshow the T&G roof sheets are only 600mm wide, not a full size sheet. I will swap these out per @Fitzroy suggestion for full sheets.

RE: someone building it. I was going to outline the rough way I wanted things built but leave them to design, procure all materials etc. I just wanted to calculate an initial set of costs so I had something to benchmark

Electrics - yes @martin.pearson good points. There will be a digger in the garden for the landscaping / levelling so agreed with the landscape that the trench will be dug as part of that and I will put the cable in. Electrics will all be surface mounted and with a small room, radial circuits and wago connectors, it shouldn't take long either!

 

[Jameshow]

Using full sized sheet OSB / ply sheets will save £20 a sheet.

I would procure all the materials in one go this getting a better discount than in dribs and drabs...

I'd dump the plaster board and paint the usb walls white.

Cheers James

 

[BucksDad]

I guess I could, but I think OSB even painted just doesn't look nice

 

[Spectric]

Electrics will all be surface mounted and with a small room, radial circuits and wago connectors,

Nice to see someone doing things without old fashioned ring mains and Wago 222 are really good, used them all the time in both Wago and Wiskra JB's yet some still use chocolate block!. Keep in mind the earthing, and extraneous conductive parts as it does cause issues.

 

[Jameshow]

I guess I could, but I think OSB even painted just doesn't look nice

Plywood then?

 

[BucksDad]

Plywood then?

Which grade of plywood paints well so you won't see the grain?

 

[Jameshow]

Which grade of plywood paints well so you won't see the grain?

Birch or hardwood...

Pine / softwood ply you will see the grain.

 

[Graham F]

The list looks pretty good to me. I've done a similar build in Maidenhead last year for my own workshop. You're welcome to pop over and have a look at it incase it helps decide on any details.
I have a great carpenter that works for me at £200/day who lives just outside High Wycombe, who I'm sure could be available if that helps.
PM me if I can assist

 

[Jones]

If you're getting someone else to do the work it's best to chat with them and give them a bit of design input, they'll know what products are available locally and may have a preference on what to use and how to do it. If a product is on a manufacturers website it doesn't necessarily mean it is available in small quantities at a reasonable price, for example I've never seen 90mm pir. On the design front I think your window is too small 15-20% of floor area is normal. Personally I would use knauf wall roll to keep costs down with insulation backed plasterboard if you want extra u value. The external osb is not needed. I would use a 600 mm stud spacing and 1x2 battens ,proper coloured roofing ones. Also I would make the box with two sloping walls and miss out the firing strips. Personally I am used to using fiberglass roofing rather than epdm ,costs are similar. I know that doesn't really answer your question but if you choose a builder you can talk through all the options with them. 10 man days should be enough to finish.

 

[martin.pearson]

I would agree with what has been said about getting the person you use to built this involved with some of the planning & material costs, I don't buy a lot of Construction material but I get a small discount from the supplier I do use & the prices I pay are not as high as the online prices, on a complete shed build I would be able to save a fair bit. If the person you use does this for a living then they will get a much larger discount so that might save some money if they pass some of that on plus as has been said they may know a better choice for materials & how to construct it.
Personnally I would have more in the way of windows, I like natural light but the downside is obviously less wall space. What would the average home office have in the way of windows because if you want to convert it easily to a home office should you move then that might be a consideration.
Plan where your machinery is going to go before you get the electrics done, not just what you have but what you think you might require in the future. Will you need a 16A supply now or maybe in the future?
There was a post not long ago about putting in an electric supply to a workshop & how best to do it.

 

[Spectric]

Personnally I would have more in the way of windows, I like natural light but the downside is

Windows allow the unwanted to see in and can be a weak point when it comes to breakins.

 

[martin.pearson]

Windows allow the unwanted to see in and can be a weak point when it comes to breakins.

Maybe I don't know for sure, if you have one window as the OP has mentioned surely that is enough to be able to see in lol, I don't have a home workshop so have no personal experience, I rent an industrial unit for what I do & have done for the past 20 odd years, reached a point in my life when I wish I had bought some where years ago rather than renting, it would be close to being mine by now.
Do removable window grates help with security?
I was just thinking a home office might allow more natural light in but have no evidence to support that lol

 

[Lazurus]

I put a 3m x 1m roof light into my 8m x 6m workshop, lots of light from that and not much of a security risk

 

[Jameshow]

I would agree with what has been said about getting the person you use to built this involved with some of the planning & material costs, I don't buy a lot of Construction material but I get a small discount from the supplier I do use & the prices I pay are not as high as the online prices, on a complete shed build I would be able to save a fair bit. If the person you use does this for a living then they will get a much larger discount so that might save some money if they pass some of that on plus as has been said they may know a better choice for materials & how to construct it.
Personnally I would have more in the way of windows, I like natural light but the downside is obviously less wall space. What would the average home office have in the way of windows because if you want to convert it easily to a home office should you move then that might be a consideration.
Plan where your machinery is going to go before you get the electrics done, not just what you have but what you think you might require in the future. Will you need a 16A supply now or maybe in the future?
There was a post not long ago about putting in an electric supply to a workshop & how best to do it.

Worth putting a ring main in capable of taking 16amp as well as 13amp even if you don't need it now.

 

[BucksDad]

Thanks for more comments. I will PM you @Graham F!

Based on everyone's feedback, I've now reduced the cost to £8250 so a nice bit of value engineering from everyone to remove £600

I've achieved that by...

- switching to full sheet plywood for the roof
- swapping over from PIR to Knauf slab for the wall insulation
- 12mm plywood internal wall finish only
- swapping out tyvek to rhinovent
- cheaper EPDM supplier
- swapping to 1x2 roof battens as suggested by @Jones and were actually cheaper

However I did add in costs for soffits, fascias, guttering + water butt which I had missed off

Yes I completely get the point about whoever does the work to take the lead and procure all materials. I'm doing a baseline cost to get the go ahead from my wife (). Seeing as best case would probably be kicking this off in March, any savings they'd get on material will probably be eaten up by inflation on these prices.

Re: Windows - will keep that in mind to go bigger. Plan was to just have a single window over where main bench would be.

16A supply - it's a 3m x 3m shed. Whilst I would love to own 16A machinery, realistically anything 16A is probably going to be too big for the space anyway.

I will now show this to my wife and try not to point out that this doesn't include any budget yet for actual woodworking tools (I don't have any), wood for a bench and some actual hardwood to actually making something

I will start a separate thread on setting up a workshop from a tools perspective, as this no doubt will be an interesting discussion

 

[Spectric]

I was just thinking a home office might allow more natural light in but have no evidence to support that lol

A solution would be roof lights, best place to let natural light in but not using cheap perspex.