Advice on new 20' x 12' workshop

[carpenteire2009]

Hi All
I've read through most of the very interesting workshop build threads here, found answers to a lot of my own questions and plenty of food for thought. I'd like to share my proposed project with you for comment, advice or suggestions. I have a very small suburban back garden, approx. 40 x 40. The largest shed I can build is 20' x 12', and this to be subdivided to create a dedicated 12' x 5' space for the garden tools, bikes etc- not generous I know and before i even start I know this shed is too small! But it's the space I have and to me it represents a lifetime's ambition to have a purpose built "man-cave" like I propose.

I need something pretty quickly, with minimum disturbance and mess so I've decided to go down the insulated metal clad route. I've looked around and the option I really want is of course the most expensive- 20 x 12', 7' high at eaves rising to 9' at the apex. Kingspan 60mm panels, roof and walls, 4 polycarbonate clear lights (rooflights) and 2 double glazed windows to the workshop area (14' 6" x 12'). Insulated steel door to the "garden shed" part and insulated steel door with 10 point locking to the workshop part. Concrete base will be insulated (50mm kingspan) and I'll incorporate a duct for a permanent electrical supply. I propose to ply line the full interior (except roof of course) in 1/2" and 3/4" shuttering grade ply. I'll use the 1/2" ply on window walls where there won't be much hanging off them anyway, elsewhere I'll use 3/4" for hanging ability. I won't stud out but glue fixing battens/ firring strips as required to cladding rails etc with panel adhesive. I'll avoid puncturing the cladding panels or structural elements where possible. All electrics will be surface mounted- probably plastic. Security wise the 10 point door is solid as hell and I have no worries with it. I'll get a couple of window grilles fabricated for the interior of the windows- I have two old roller blinds that can be cut down to suit. I'm going to use a cheap floor paint on the floor (powerfloated I think) and place rubber matting at the two work benches to save my chisels! I plan on using an oil filled rad for intermittent heating, it shouldn't cost a lot to run and keep the dreaded rust at bay.

I looked at just getting a cheaper uninsulated shed and studding it out myself, insulating etc but the cost of materials alone was eye watering and there is a lot of potential for interstitial condensation and mould issues if not done correctly. I need to keep the building height on the low side (I'm not tall anyway) to keep within planning restrictions and so as not to upset my neighbour. This is a once-off project for me, I have to compromise on size but I don't want to compromise on quality or comfort. The fun part of this build for me is fitting out the workshop, building the storage and organising it as best I can- my dear wife has sanctioned the build cost of my "Rolls Royce" option so I can hardly refuse ; )

What do ye think?

 

[Random Orbital Bob]

well it sounds pretty robust indeed. I've no experience at all with the metal doors you mention so cant comment. The comfort factor sounds well thought through and I agree that its the only way to go if you expect to get year round use. My only reservation which I accept is entirely a personal thing, you seem awfully gleeful about how high the budget is. You call it the Rolls Royce option. Were that my decision I might back away from the high spec of the building a little (those doors, the ply etc) and keep as much of the cash as possible for tool investment since that's where I'll want the quality downstream. The building is lovely n all but once its up, its warm and its secure and doesn't look an eyesore...its done....now you want to get in there and make stuff and the decent machine tools don't come cheap as doesn't interesting wood. Maybe you've got that covered already or are more into hand tools and therefore its not such an issue. Just a thought that all. Being a Yorkshireman, my personal view is always to consider the cost of what comes next...

 

[RobinBHM]

I expect you already know this but regulations are:

planning regs: max 2.5M high if within 2.0m of boundary

building regs: max 15 square metres if within 1.0m of boundary or will need to be constructed in non combustible material.

I'm currently building a shed 18'0 x 9'0 (5.4m x 2.7m). My construction is 4 x 2 studwork, 18mm osb, tyvek housewrap, 25mm tile battens then siberian larch cladding.

To be honest it was pretty quick to build the framework, the base was much more work. I did a scale drawing, designed the side frames in modules and then did a cutting list for every part and cut them all in one go.

I would consider osb board rather than ply, it is water proof (OSB3) to some extent and will take a screw very well.

To keep within the height restriction the shed is basically a flat roof with just a 100mm fall. The problem with height is that it is taken from ground level, so by the time you have allowed for base, floor insulation, roof joists and insulation the height is always tight. If you are more than 2 metres from the boundary then this is less of a problem as the height limit is 3.0 or 4.0 for a apex roof.

http://www.planningportal.gov.uk/permis ... buildings/

 

[carpenteire2009]

Thanks for the feedback. In relation to planning, I'm in Ireland so planning regulations are substantially different and I am compliant as an exempted structure. In relation to the cost, believe me, I am concerned but I am probably different to most men that I know, who have a lovely big shed or garage BUT nothing in the blooming things except garden stuff, bicycles and a clapped out gas BBQ! I on the other hand have a very substantial hand tool kit (and some portable power tools, a router table, grinders, pillar drill, small bandsaw etc and not just wood work tools either) built up over a 15 year period when I first started on the slippery slope! Up to now I had my little hobby set-up based in a part of someone else's workshop, but business closure means I must now find a new home for it all. I had considered a self build but with a young family and very busy lives I just know that it would be a slow and tortuous process on my own AND I don't have time on my side- I need to rehome my kit in the next 2 months or thereabouts. As for the lining- I don't like OSB, I've seen what happens when the stuff is mistreated and I'd much prefer shuttering ply. The place I currently use has this finish and I do like it- easy on the eye, warm and great for taking a fixing. Thanks guys.

 

[Random Orbital Bob]

I've just spent a few months helping a local friend of mine build his first workshop and much like Robin above, he used 4x2 stud work and clad the inside with OSB. The outside he's done with feather edge laid horizontally. I'm with you on the appearance of OSB. I also find it undesirable to look at though having worked with it (11mm not the 18) it is pretty robust even if it gets a bit wet given the amount of resin in it. So OSB is definitely the money saving option. My pal is planning to paint his but I also find white coated OSB not to my taste after a few years so if I could justify the cost I would prefer ply. It's justifying the cost I always struggle with. However, as you say you've already got a lot sunk in tools so that does change the outlook somewhat. Rolls Royce it is then

 

[colinc]

Hi,

I wonder if you might get a better looking result using something other than Kingspan for the walls? I'd go for Siberian larch, but for my own I used Cedral for non-combustibilty. Normal timber framing with ply inner, insulation, osb, membrane, etc., as detailed in several threads here works great. Using king span is ok, but trimming the openings properly and neatly needs purpose made flashings to do it right, much easier in timber.

Using Kingspan insulated panels makes sense for the roof but I wonder if roof lights aren't an unnecessary complication and expense as you really need the purpose made double skin units to match the roof sheets. You'll find you need lights anyway and it sounds like you have adequate windows. Assuming an apex roof, You'll just need a purlins at the ridge and an eaves member as the sheets will span ok. The lining face of the king span panel is a nice white polyester surface so nothing more needed up there. It reflects light around nicely. I wouldn't ply line the roof.

You didn't mention a timber floor I think? One of the best features of my shed is the over-slab dpc, battens and insulation topped with 22mm t&g chipboard and painted with floor paint. It makes a real difference.

Here's a link to my shed build, just to show what I did. I have to admit it still isn't quite finished but that's because I have been busy using it!

my-new-workshop-t71387.html

Regards,

Colin