Workshop Design - well it's a build really.

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Dibs-h

Established Member
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Location
Bradford, West Yorkshire
After reading countless posts about other peoples workshops and feeling bloody envious at times - I'm having the plans drawn up for mine with the intention of the build starting in Jan 09.

The plan is to build it with a pitched roof, on the end of a single garage utilising the end gable wall. As the front of the garage has a gate blocking off the view into the garden - the workshop is to be 3.0m wide (tad wider than garage) and 10m long.

Single skin blockwork with piers, infill piers with stud\insulation and board over. Have a choice of concrete floor or joists (haven't decided yet). As part part of the floor might be below ground level (the ground slopes down from the end of the garage) might be concrete - ideas\input welcome.

It has to be blockwork, then rendered with limestone chippings and clay tile roof - it's a conservation area and neighbours (although very nice, have covenants on that section of my garden) to match in with house and existing garage.

As the roof will be rafters\purlins - I'm loath to use steel as the 2 purlins will each need to be 10m and that weighs a sh*t load - access is slightly restricted. Was wondering if TGI beams or glulam could be used - struggling to see why not. Any thoughts?

Haven't looked at the span tables yet - will be having a chat with the structural engineer this eve about the sizes required.

I'll post up some piccies in the next day or so.
 
Sounds great!!!
.....except for the width. Three metres less 210 x2 equals a floor width of only 2580, or 8'-5".

Couldn't you build it out of studwork, and then batten out, wire and render? It would look exactly the same from the outside, and save you 200mm inside.....

I am not sure why you need purlins for such a narrow building? Why not just a normal cut roof or trussed roof?

Mike
 
See what you mean - might make that 3m on the inside then, can't seeing it being an issue.

I would have thought with a pitched roof one would still need purlins, if not using a trussed roof - which I want to stay away from. I'd much rather not use trusses as it would mean that the "collar" effectively reduces the ceiling height down to around 8 foot (eaves will be around 8 foot). I'll have to check the span tables - been ages since I last looked.

I'm building right up against the boundary so would struggle to do anything with that part of the wall that is below the top of the boundary wall.
 
If you must use purlins I would at least consider two "A" frame type trusses of substantial build at thirds positions to give you the head height and reduce the need for massive purlins. I wouldn't be happy in a building that length without tying the two sides together midpoint anyway, if it isn't trussed.

Alan
 
Sounds a great size - its about the same as mine; there's two of us each running a cabinetmaking business from it AND we've got a spray booth in there!

However, watch that ceiling height. The bare minimum should be the diagonal of an 8x4 sheet plus a few inches for clearence of your light fittings.

DAMHIK!

Dan
 
It sounds great. I wouldn't use a purlin construction myself i'd buy or make raised tie trusses. Mike's advice about width is very good also.

If you go for timber frame construction make sure you set the roof rafters out directly over the studs, i've seen a couple of jobs recently which i would be concerned about.

Good luck

Where in Yorkshire are you?
 
Dibs,

A raised tie on a normal trussed roof is certainly the way I would go.....whether you cut the roof on site yourself or buy pre-made trusses. There is absolutley no need for purlins of any description on such a small and simple roof.

Mike
 
Dan - that was the thinking, the eaves will be around 8 foot and I had the 8x4 sheet on a diagonal in mind.

Matty - Bradford way.

Matty\Mike - I did have a look in Trada timber tables and for the clear span around 2.1m, I wouldn't need purlins, but speaking to my Structural Eng chum, he did agree with a local timber supplier that Trusses, either with a traditional tie or a raised tie would be the way to go. Otherwise the lateral thrust wouldn't be restrained.

Although he did suggest that in the past he has solved similar issues with steel beams spliced together. I am loath to use steel though - fire protection and man handling it spring to mind.

Having thought about it - I'm more inclined to go for the raised tie trusses. A local firm quoted me around 1K for 18 of them. They sent me the profile of the truss - so I suppose one could be sneaky and used that - the sides were 7"x2" though

Has anybody made their own raised tie trusses? What connectors have been used?

p.s. Many thanks for the replies!
 
All the time Dibs......... simple M10 bolts will be fine for securing raised ties. Nail the joist in place first, then drill and bolt. easy.

Another tip.........try and design your roof so that your rafters are at 600 centres rather than 400.........that way it is easier to work on them and also acees for storage is better if you leave the rafters open. Personally, I have lined my ceiling with stirling board, and have storage access through the gable........which enables me to have insulation at joist level.

Mike
 
Mike Garnham":2vynng73 said:
All the time Dibs......... simple M10 bolts will be fine for securing raised ties. Nail the joist in place first, then drill and bolt. easy.

Another tip.........try and design your roof so that your rafters are at 600 centres rather than 400.........that way it is easier to work on them and also acees for storage is better if you leave the rafters open. Personally, I have lined my ceiling with stirling board, and have storage access through the gable........which enables me to have insulation at joist level.

Mike

Mike

Thanks for that. I rang another company and they quoted around £500 all in for the same trusses - bit startling to find such variation in price, some of these companies must think we are made of money.

I did intend to have the trusses at 600 centres - with the bottom tie up 1m from the wall plate level. This would give me a nice vaulted ceiling. The bit extra - above the raised tie - that seems so little, makes you wonder whether you could actually use that for anything useful. The 0.5m is actually from the top of the raised tie to the ridge and considering the "rafters" are in the region of 150mm, one isn't left with a huge amount of space.

To give it that extra security - inclined to sheet the outside with ply - I'm not very comfortable with the idea of some toe-rag pulling a few tiles out and easily making their way thru 600 spaced rafters. Also it should help locking everything together and reduce the lateral thrust at the wall plates.

I estimated that the timber to produce the trusses would be in the region of £150-£200 but did fancy doing it myself - did enjoy redoing the roof on the house itself several years ago. So may not even get pre made trusses, even if they are cheaper.

Also fitting insulation in between the rafters is what I had in mind - Kingspan\Celotex. I've got some Tyvek and laths left over from the house roof.

With respect to the fixings - how many per joint - get the impression it's 1 M10 bolt?

On the pre-made trusses - there is a single vertical piece from the raised collar to the underside of the ridge. Would I be correct in assuming that this too would be needed on site made trusses?

Cheers

Dibs
 
Dibs,

that single vertical piece to the ridge is a called hanger, and its function is to support the joist to prevent sagging. Given that your span is so small, and the joist won't really be loaded given the dimensions you give, you needn't worry about a hanger.

Having said all that, because your building is on the boundary and over 15 sq. metres, you will require Building Regs approval for this job. The Local Authority will want calcs for the foundations and for the roof.........your friendly structural engineer will come in handy...

This is an obvious candidate for a "Building Notice" rather than "Full Plans Approval".......just be sure to inform the LA before you start work.

Mike
 
Update - In between the millions of other things that get in the way, finally got the plans submitted and had the Planning Officer out this morning.

Bit of an change on the original idea - which was a 10m x 3m workshop on the end of an existing garage - replacing the garage as well. Thought what the hell, only do it once.

New scheme - new garage 4.2m x 6m with a suspended concrete floor (the land drops off after the end of the garage), giving me a useable basement underneath of approx 6 feet tall. New workshop on the end of the garage - 4.2m x 7.5m.

Thought I'd reduce the workshop length slightly - now that I've also got the basement under the garage.

Hopefully get the permission by mid May, so looking to start the build by the beginning of June.

I'll post a copy of the plans up shortly.
 
I'm not to fazed by the project as whole - more the suspended concrete floor that's having a 2 poster car lift bolted to it.

Here a shot of what it will look like from the neighbours side,

Workshop_Side.jpg


The only changes (mid construction) are likely to be the deletion of the door on the end and the internal wall dividing the workshop. From previous experience - far easier to make the final changes as an amendment

And here's the plan view,

Workshop_2.jpg



The step down from the garage to the workshop is actually in the region of 5 foot, so lowering the floor marginally should get me a basement around 6 foot. Even if it doesn't, should be very useful for strorage.
 
Hello Dibs, good luck with your workshop project, sounds great. Lots of hard work though I'm sure.

Hope to follow progress. Cheers Tony.

PS - Don't forget the old pythagoras for the measurement of that 8 x 4
 
8 x 4 - someone mentioned that before. The roof of the workshop is going to be trusses with the collar being near the top, to ensure at least 8x4 sheets clear on the diagnonal.

Off to get some Rosemary tiles for the roof this eveing - even though planning permission hasn't come thru (the Planner said he disn't see any issues cropping up) - at around £280 for over 4000 tiles is too good to give up especially as it's about 20 miles away.

Just don't look forward to loading, transporting and unloading. :(
 
Update - the chap who "sold" me the rosemarys decided he's sell them to someone else. Thankfully no deposit paid nor transport hired! So no neck to wring.

But managed to get the same number - perfect colour match, as opposed to close - from 20 miles the other way, for about the same money. You don't realise just how much space 3,000 tiles take up, most of the patio has disappeared under them

Rang the planners today - PP has been granted, I should have it in writing by Monday morning. By which time the CofE who own next door will have stated in writing the process they want following regarding the drystone boundary wall (i.e. Party Wall).

Will post up pictures as soon as we start with groundworks.
 
Hi dibs-h

inconsiderate who ever but that garden wall there :lol: :lol: pity it wasn,t a bit more to the left dam shame that, look forward to follow the build on your shop though .hc

Ps the boundary wall is it a party wall, or is it yours, is it not possible to build that wall high for just the length of the workshop to gain a bit more width internally in the workshop . :?: :wink:
 
head clansman":39pwzhls said:
Hi dibs-h

inconsiderate who ever but that garden wall there :lol: :lol: pity it wasn,t a bit more to the left dam shame that, look forward to follow the build on your shop though .hc

Ps the boundary wall is it a party wall, or is it yours, is it not possible to build that wall high for just the length of the workshop to gain a bit more width internally in the workshop . :?: :wink:


All our boundary walls are party walls - with a small exception at the front which is actually mine.

Almost all our walls are dry stone wall - with it being a conservation area - can't see folk being too happy if a section of it gets replaced. Besides I kinda like them.

The workshop will be 3.6m x 7.1m internally - with a storage area underneath the attached garage of approx 3.6m x 5.6m (around 4-5foot tall) - how big do you want it? :wink:
 
Update - got my planning permission - just shy of the 8 weeks quoted by the planning department and the Management Agents (for next door) came back with acceptable conditions in relation to the dig, and confirmed that the Church Commisoners are happy to give their consent.

It turned out that the wall is actually mine, as confirmed by an extract from the original deeds - circa 1918. But I suppose it's a case of trading some rights for others - i.e. giving next door some say over it's appearance and consulting them, in return for them easing the restrictive covenant on the strip of land on which the workshop\garage is being built.

Had 2 chap in to quote for the groundworks - he seemed interested but never got back to me. The other chap who had been before - quoted a reasonable price, so I asked him back round in the first several days of June - just to go over stuff and make sure there was no mis-understanding.

When asked,

1. There are 2 buildings?
2. Are you sure you want a Building Regs certificate?

The TV programmes I watch - when they are on - are either Norm (workshop or This Old House) or Holmes on Homes, and as Mike Holmes says "If they say you don't need a permit, walk away."

When this chap started suggesting doing this without involving Building Regs and ignoring the Structural Engineers advice - I thought "no thanks".

That left me stuck thinking WTF now? And the plan had been to break ground on the 1st weekend of June, now 2-3 days away.

Well Ebay came to the rescue, On Sat eve, the following turned up,

digger.jpg


Cost £50 for the day & £20 for collection & delivery - fully fuelled up and with a spare jerrycan.

There was a path running down the garden which seemed to have several stone flags, so we thought we'd take them up first. We soon realised that the whole path was stone flags - something I had never realised having lived there for around 10 years - with a thin skim of concrete over the top.

path_flags.jpg


You can just make out the beginning of the path at the bottom of the steps on the right of the picture. It's the darker flags - around 10 inches wide. Awesome find - will be putting them back at the end for the new path.

A friend came round professing to have driven one a fair bit, so we fired it up and got some topsoil removed in about 2 hours. What made me somewhat unhappy was the number of times he struck the drystone wall with the bucket,

rear_of_existing_garage.jpg


That's a picture before any work started - but you can see the wall. I realised due to some eye condition he has - keratoconus, his perception of depth can be poor.

So on Sunday morning at 09.30 - I never get up that early on a Sunday, I got on the digger, reasoning that having driven forklift trucks a lot in the past - it couldn't be any more difficult, so after a few hours,

topsoil_cleared.jpg


And then after a few more hours later ended up with this,

clay.jpg


The topsoil etc. removed from the dig will just be spread round the rest of the garden to level it out - it's a bit unlevel and bumpy.

That's the base for the workshop on the whole. Even though the site has been cleared to the back of the existing garage. The plan is to build the workshop first - empty out the garage first - demolish it and then build on the workshop.

The white line marks out the approx footprint of the workshop - 7.5m long by 4m wide, and it will be adjacent to the boundary wall.

I put up a string line - to get an idea of how much of a "cut" was required to get it reasonably level - or at least minimise the "fill" at the bottom.

The digging stops short of the boundary wall - the advice from the engineer has been to do r\c slap with integrated groundbeams, the one nearest to the boundary wall to be stepped back 0.5m, with the slab cantilevered over the beam.

The next picture shows the stepped dig a bit better,

wall.jpg


Standing on the white line, a part of which is showing in the picture above (at the bottom left) - i.e. the separating wall between the garage and workshop, and facing the back of the existing garage, shows,

basement.jpg


shows the height of the existing garage basement\pit to be now around 6 feet. So this is making me seriously considering dropping the floor in the new garage, i.e. make the foundations lower than those of the workshop by say 2 feet - to get a full basement under the garage of say 6 to 6.5 feet. The top of the opeining at the rear of the existing basement is at head height - i.e. 6 feet high, so I am optimistic it should be manageable.

Now it's just a case of "fettling" to get things a bit more level and marking out and excavating for the groundbeams. Will try it by hand - they need to be 18 inches deep, if it seems too much like hard work - I'll get the digger back in.

The following picture shows the remainder of the garden - so SWMBO and the kids still have most of it left,

garden.jpg


Now for some advice - the original plans had been to build it in concrete block, single skin with piers say every 2m. Now the length of the building is 7.5m long and the width is 4m and I was planning on using raised tie trusses. With stud infill between the piers and some insulation.

My engineer chum is suggesting that I build the walls by laying the blocks on their side - i.e. a wall 9 inches wide. Something about being better able to resist the forces from the trusses - I can see what he means - a wall 9 inches thick would result in a more stable building, but the question I have is that would my original construction method result in an unstable building? In the workshop I am willing to lower the truss ties so that I can clear a 8x4 sheet on a diagonal and nothing more, resulting in the thrust on the wall being less than if the tie was as high as possible.

Although this will be the scenario for the garage - I would need the trusses to be somewhat higher.

On a related note - I bought approx 3500 Rosemary roof tiles for < £400 all in, so pleased with that, considering local salvage yards were quoting me £250 per 1,000 tiles plus delivery. Plus the colour match is spot on and includes enough halfs and tile & halfs to do the job.

p.s. I've never excavated footings or done any building on this scale, so any advice would be greatly appreciated. If you see anything in the pictures that could be better, etc. the advice would be much appreciated.
 
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