Workshop advice - building regs and diy timber framing

[HarryB2019]

Hi Everyone,

I am looking for some advice for a new workshop build I am in the initial stages of planning. I have always had an interest in completing my own timber framing project - my initial plan is to build a 9m x 5m workshop using green douglas fir sourced within kent (where I am based). Does anyone have experience in building regs for timber framed buildings? From what I have gathered, the beams must be structurally graded, which I believe the sawmill can do for me. What I am unsure about is the joint selection/ frame design - do I need to pay a structural engineer with experience in timber framing to assess my frame design for building reg approval?

Any general advice would be extremely appreciated. I am aware that there are plenty of timber framed garage kits etc. with calcs all completed which I could purchase and modify into a workshop, however I want to go down the DIY route both to save money and for the learning experience.

Best

Harry

 

[Molynoox]

Hi Harry, good luck with your build, sounds fun! I am just doing one myself, similar size, but I kept it within permitted development and made sure I complied with everything needed to make it exempt from building regs. You are not going to be able to do that with your size as it exceeds the 30m2 max, which you probably know. I can't help with your questions, but make sure you do a build log so we can all check it out

 

[mikej460]

I enjoyed watching this workshop build on The Restoration Couple. He used Douglas Fir but if you plan to use the same size timbers you will need to be vey fit or have help!
MY NEW WORKSHOP! Cutting the Beams - Serious Sawmill Action! - YouTube
You must start a thread covering your journey and with lots of pics!

 

[Adam W.]

Depending on the size of the douglas fir, I would use mortice and tenons and post and beam construction.

From my shed build....

 

[Adam W.]

More...

 

[Cabinetman]

Very nice but I think you will scare poor Harry half to death if he thinks he has to use timbers on that scale!
I imagine he is doing it more like house construction with 2x4's? Ian

 

[HarryB2019]

Hi everyone, thanks for your replies!
@Cabinetman I want to approach it as a traditional timber framing project, and so the post and beam construction of @Adam W. is indeed the type of thing I am considering. I have access to a forklift which should make the raising of such heavy timbers viable, plus some strong mates!!

@Adam W. - did your shed have to comply with building regs or is it under 30m2?

 

[Adam W.]

Very nice but I think you will scare poor Harry half to death if he thinks he has to use timbers on that scale!
I imagine he is doing it more like house construction with 2x4's? Ian

Oh!

I didn't think of that, sorry if I've put anyone off.

 

[Adam W.]

Hi everyone, thanks for your replies!
@Cabinetman I want to approach it as a traditional timber framing project, and so the post and beam construction of @Adam W is indeed the type of thing I am considering. I have access to a forklift which should make the raising of such heavy timbers viable, plus some strength mates!!

@Adam W - did your shed have to comply with building regs or is it under 30m2?

I think it's over 30 square meters, but it's in Denmark so the regulations are different.

I've built oak framed extensions in the UK over 30 square meters and there was never any need to supply framing calculations for the walls, and I just made sure that the roof timbers were the right size. That is easily done with a span table and you should be able to get one off the web.

The posts are very strong in compression, but you need to have an adequate thickness to resist buckling and the sole and wall plate don't need much consideration if the span of the wall plate is not too great between the posts.

I'd try and use 5" or 6" timbers for the posts if you can afford it. Douglas is very strong anyway and it will give the building regs bloke a sense that you are over engineering it. It's also nice to build with proper sized timbers if you are going to frame it in the traditional way.

I built mine alone, but I've done stuff like that before and have a small aluminium gantry crane and all the lifting gear to hand, so it was pretty straight forward.

There's a course at the Weald and Downland museum called "Timber framing from Scratch" that is run by Joe Thompson who's an excellent tutor. It'll teach you everything you need to know about framing and the museum is a really nice place to go for inspiration.

Ps.

Mine's got a green roof on it with a deep growing medium, so it needs to be beefy. I also had the timber left over from all the framing I did on the house and I wanted it to fit in with the original framing, which is why they are so big.

 

[HarryB2019]

I think it's over 30 square meters, but it's in Denmark so the regulations are different.

I've built oak framed extensions in the UK over 30 square meters and there was never any need to supply framing calculations for the walls, and I just made sure that the roof timbers were the right size. That is easily done with a span table and you should be able to get one off the web.

The posts are very strong in compression, but you need to have an adequate thickness to resist buckling and the sole and wall plate don't need much consideration if the span of the wall plate is not too great between the posts.

I'd try and use 5" or 6" timbers for the posts if you can afford it. Douglas is very strong anyway and it will give the building regs bloke a sense that you are over engineering it. It's also nice to build with proper sized timbers if you are going to frame it in the traditional way.

I built mine alone, but I've done stuff like that before and have a small aluminium gantry crane and all the lifting gear to hand, so it was pretty straight forward.

There's a course at the Weald and Downland museum called "Timber framing from Scratch" that is run by Joe Thompson who's an excellent tutor. It'll teach you everything you need to know about framing and the museum is a really nice place to go for inspiration.

Ps.

Mine's got a green roof on it with a deep growing medium, so it needs to be beefy. I also had the timber left over from all the framing I did on the house and I wanted it to fit in with the original framing, which is why they are so big.

Ok, interesting about your experience with extensions over 30m2. My suspicion is that with some consideration getting the structure to pass building regs won't be too hard, my difficulty at the moment is finding a internet resource which specifically goes into the requirements for traditional timber framed builds. As you say, figuring out just the roof shouldn't be too difficult however.

It's perhaps worth a call to the local building regs department. I also might have a look on the internet for a timber framing forum and ask there, presumebly people involved in traditional timber framing have to do these type of calcs all the time.

 

[Adam W.]

Structural engineers do the calculations and framers do the framing. I think you'll be hard pressed to find a clear answer on a forum.

I don't see the requirement for loads of calculations if it's not going to be lived in. You'd be better off talking to building control at your local council. I've always found them to be very helpful.

 

[Cabinetman]

Hi everyone, thanks for your replies!
@Cabinetman I want to approach it as a traditional timber framing project, and so the post and beam construction of @Adam W. is indeed the type of thing I am considering. I have access to a forklift which should make the raising of such heavy timbers viable, plus some strong mates!!

@Adam W. - did your shed have to comply with building regs or is it under 30m2?

Haha, well all good there then! Can’t imagine it falling foul of the regs at those sorts of sizes though. Always wanted to build something like that myself.
I just helped future son-in-law to build a new front on an old car garage in the USA the other weekend, and using 2 by 4’s either side of the doorway we had to use three in tandem each side for it to reach code, and the header/lintel was made from a sandwich of two lengths of 8 x 2 with 1/2 ply between to bring it up to 4”. All this when there wasn’t any weight at all on it from above. No point arguing about it though. Ian

 

[mikej460]

Haha, well all good there then! Can’t imagine it falling foul of the regs at those sorts of sizes though. Always wanted to build something like that myself.
I just helped future son-in-law to build a new front on an old car garage in the USA the other weekend, and using 2 by 4’s either side of the doorway we had to use three in tandem each side for it to reach code, and the header/lintel was made from a sandwich of two lengths of 8 x 2 with 1/2 ply between to bring it up to 4”. All this when there wasn’t any weight at all on it from above. No point arguing about it though. Ian

Same applies to building a dormer in the UK, no real weight but thems the rules