A question of construction and materials.

[Lazurus]

I am in the position of having a purpose-built workshop for the first time in my life, this is just prior to retirement. I am looking at a 10m x 5m workshop in our back garden (subject to planning) It is currently in the design and application process. Initially I was going for a traditional double skin brick construction with insulation in keeping with the garage and bungalow – however I like the idea of a more modern looking dark grey cladding. The attached drawing shows the preliminary design. I am looking for low maintenance and, in the future, when I can no longer use a workshop converting the inside to an annex or sun room. So, I intend to put water and drainage utilities in at the point of build ready for future change of use. Can I ask advice on the best construction method and what is required in structural design to use exterior cladding, and, which type would be best?

 

[Cabinetman]

Wow, who is a very lucky boy Lazarus!
Sorry I can’t help with the technical stuff except to say whatever level of insulation you are told, I would recommend you add a whole lot more, a bit more expensive now will pay off hugely in the future. Ian

 

[Jameshow]

I'd go for a simple 4x2 frame on 2ft centres 4" OSB / ply each side rockwood polystyrene or celotex insulation.

You want a slope on the flat roof. EPDM rubber / fibreglass roofs are good. But more expensive than felt.

Cheers James

 

[spb]

I can't say too much about construction methods, but do bear in mind that at that size you'll fall under building regulations as well as planning. Most of the advice you'll find on here is for smaller builds that don't have to comply, so just be careful on that front.

 

[Sheptonphil]

sounds a very exciting project.

Save yourself a whole lot of heartache for later by doing things wrong on a build like this, by employing a professional architect right from the get go. They will be conversant with local bylaws and what local authorities deem acceptable. They could save more than their cost by getting it right first time. Building control will be involved before you cut the first turf, you need to keep them on side. Construction methods on a dwelling of this size and for future habitable occupation will be vastly different to our standard workshop builds.

I’d be very wary of taking any advise from any forum except as a brainstorming excercise for ideas to pass through your architect.

 

[Lazurus]

I have gone an architect working on this for me as rightly said it is not a small project. Initially I was going for a standard brick build but looking at some of the newer composite claddings available I like the idea of this as a finish. I just want to be sure that the route I steer the architect down is feesible and future proof. Many thanks for the input so far.

 

[DBT85]

The Hardiboard @Sheptonphil used would probably sort you for cladding purposes. Just bang it up, no need to paint it or maintain it.

 

[HOJ]

Construction methods on a dwelling of this size and for future habitable occupation will be vastly different to our standard workshop builds.

I’d be very wary of taking any advise from any forum except as a brainstorming excercise for ideas to pass through your architect.

The big question at this stage is what it will ultimately be used for, construction methods for "residential" use as Sheptonphil has outlined, will be a totally different ball game, and consequently a far higher M2 cost, Building regs will also need SAP & "U" value calcs, possibly along with Engineers input, and if close to a Broad a Flood risk assessment along with a Landscape Character Assessment.

I have to say if I had the opportunity to build I would go residential, designing for a layout and provisioning for facilities now, in the long run you could potentially generate a tidy income from a holiday let or Air B & B, especially being on the Broads.

I have built a few "Annexes" using timber frame methods and have used both cement and timber cladding solutions, dependent on the "local vernacular" style, and how the planners have directed us, more so with the Broads Authority, they also offer free pre-application advice, which is worth using before you get too far with
a full design drawn up.

 

[Sheptonphil]

The Hardiboard @Sheptonphil used would probably sort you for cladding purposes. Just bang it up, no need to paint it or maintain it.

The cladding I used, in my case for compliance with ‘predominantly non combustible’ clause, was HardiPlank, a cement fibre board cladding system that as DBT85 says is all but maintenance free and is available in 21 colours. Certainly no painting for 15 years+. Three times the cost of timber cladding, but worked better in my build situation than brick/block, which was my only alternative.

 

[Lazurus]

Hardie board looks the way to go, so would a few courses of brick then a timber frame be the way to go, or would a block inner with insulation and framing then Hardie board cladding be better?

 

[DBT85]

Your achitect will tell you whats viable, but I don't think I'd bother with block and then frame the outer. IF you wanted to get really fancy you might brick plinth, frame above with insulation between and then insulated plasterboard the inside which will bridge the cold spots. May be required anyway. No idea for passing building regs. Mine was 29.99m2 so I was allowed to make mine from matchsticks and firelighters!

 

[Lazurus]

Yes the architect has recommended a few courses of brick, insulated timber frame above this with hardie plank cladding and a pent edpm covered roof with hidden gutters, now awaiting further drawings.

 

[Blackswanwood]

My ongoing build is being done to the standard required for residential use. It's pretty bog standard brick and block with Kingspan/Celotex cavity board insulation. Due to planning considerations I only had the option using brick for the outer skin but agree the Hardie Board option looks good.

I looked at timber frame construction but the price benefit wasn't there due to the scale. Getting to the standard for residential use was mainly down to the insulation - it didn’t take much.

Your design looks smart with plenty of natural light. Mine needs steelwork to accommodate something similar due to the weight of the roof which your design should avoid also.

Good luck with it.

 

[Iestynd]

Could you use SIP pannels? Roof and walls, quick to deploy, affordable, extreemly warm and of course can be clad however you see fit.

Having built a number of extensions within Building regs, i would seriously consider this route in the future.

Good Luck - I'm very envious.

 

[Lazurus]

Could you use SIP pannels? Roof and walls, quick to deploy, affordable, extreemly warm and of course can be clad however you see fit.

Having built a number of extensions within Building regs, i would seriously consider this route in the future.

Good Luck - I'm very envious.

I hadnt come across these, they look ideal - thank you.

 

[Shane1978]

I hadnt come across these, they look ideal - thank you.

Im at a similar (a few months behind) point in my workshop/shed/future-potential-residential-use build. It will be a fair bit smaller than yours (6x4) but I’ve always liked the idea of SIPS. I don’t know many people who have heard of them, and that puts me off (there are so many videos on timber framing, which make me feel more supported information-wise) but if you do consult your architect I’d love to hear what they have to say about SIPS.. do they think it would be easier? What about the cost?

 

[rs6mra]

Im at a similar (a few months behind) point in my workshop/shed/future-potential-residential-use build. It will be a fair bit smaller than yours (6x4) but I’ve always liked the idea of SIPS. I don’t know many people who have heard of them, and that puts me off (there are so many videos on timber framing, which make me feel more supported information-wise) but if you do consult your architect I’d love to hear what they have to say about SIPS.. do they think it would be easier? What about the cost?

SIPS have been around for several years and I have yet to come across the downsides to it. I have always always always asked myself the question as to why it isn't that popular. They are easy to erect & have good insulating properties. I wonder what i'm missing......

 

[Shane1978]

SIPS have been around for several years and I have yet to come across the downsides to it. I have always always always asked myself the question as to why it isn't that popular. They are easy to erect & have good insulating properties. I wonder what i'm missing......

Do you know anyone with experience building/designing with them in London/South East?

 

[rs6mra]

Do you know anyone with experience building/designing with them in London/South East?

Sorry, I can't recommend anyone. My only experience of them is seeing them being put together on several TV programs including Grand Designs and I also looked into it a while back when I spoke to a firm at the Ideal Home exhibition. Some companies that specialise in Garden buildings use them also.

 

[Keefy.]

There's a company called Future SIPS (in Gloucestershire) that makes garden rooms (could be used for a shed/workshop I reckon).
No affiliation, just investigating what they offer.