Workshop Build - 5m x 3m

[g8dy]

Hi all, I'm finally progressing on my build after getting LOTS of help from this forum on how to approach my build.

I will first extend my current concrete base with a trench layout and will be following Mike's shed design (I'll be laying down concrete lintels and building from that)

The first step was to demolish the old shed and greenhouse, dig up the paving stones, and start digging the trench. The plan is to lay 150mm of MOT Type 1 and then 150mm of concrete with rebar. Will also install rebar dowels to connect old and new concrete. I'm glad I decided to break up these paving stones and not build directly on top as the mortar below it was approx 60mm deep and very crumbly. Probably would have been fine but I want this shed to last 20+ years so might as well try and do it properly

Trench digging finished. It's approx 300mm wide and 300mm deep

Laying sub base. Using MOT Type 1. I had to wheelbarrow all this through the house as it can only be dropped off at the front of the house.

That's all the progress for now. This has taken me over a month to do so far as I only have had a few hours spare here and there. I was hoping I'd get this built within a month but realistically it probably won't be finished till next summer, I've been putting off this part because I'm a little nervous about pouring concrete, but need to just crack on and give it a go.

I've already hit a snag in that I underestimated sub-base volume so I need another 1tonne bag delivered to bring up the sub-base level to 150mm and recompact it. Currently, it's sitting around 80-100mm thick.

Lesson learned #1 - I should have just gone with 100mm sub base and 100mm concrete base. Would have been more than enough for a workshop, cheaper, and less labour-intensive.

 

[Jesmona]

Hi all, I'm finally progressing on my build after getting LOTS of help from this forum on how to approach my build.

I will first extend my current concrete base with a trench layout and will be following Mike's shed design (I'll be laying down concrete lintels and building from that)

The first step was to demolish the old shed and greenhouse, dig up the paving stones, and start digging the trench. The plan is to lay 150mm of MOT Type 1 and then 150mm of concrete with rebar. Will also install rebar dowels to connect old and new concrete. I'm glad I decided to break up these paving stones and not build directly on top as the mortar below it was approx 60mm deep and very crumbly. Probably would have been fine but I want this shed to last 20+ years so might as well try and do it properly

View attachment 168077 View attachment 168078

Trench digging finished. It's approx 300mm wide and 300mm deep

View attachment 168079 View attachment 168080 View attachment 168081

Laying sub base. Using MOT Type 1. I had to wheelbarrow all this through the house as it can only be dropped off at the front of the house.

View attachment 168082 View attachment 168083

That's all the progress for now. This has taken me over a month to do so far as I only have had a few hours spare here and there. I was hoping I'd get this built within a month but realistically it probably won't be finished till next summer, I've been putting off this part because I'm a little nervous about pouring concrete, but need to just crack on and give it a go.

I've already hit a snag in that I underestimated sub-base volume so I need another 1tonne bag delivered to bring up the sub-base level to 150mm and recompact it. Currently, it's sitting around 80-100mm thick.

Lesson learned #1 - I should have just gone with 100mm sub base and 100mm concrete base. Would have been more than enough for a workshop, cheaper, and less labour-intensive.

Keep it up mate, I am still plodding away at my garage conversion. 5 x 3 is a great size space

 

[g8dy]

UPDATE #2

Forms builts, rebar tied in and dowels epoxy'd into the older slab



Concrete poured, it was 150mm deep and took approx 3-4 hours by myself, I was definitely over thinking the process, hardest thing was remembering how many buckets of ballast I added to each mix



Left the forms on for 72 hours and then removed.



Now its time to start laying the concrete lintels these are 900mm long. I have a 40mm drop across the 5m length of the concrete base. This first lintel is the highest point so I thought I'd start from here and then pack up the rest with some sort of shim. Metal and slate shims are quite expensive and I need to make up quite a bit of height. Unsure whether to just use a lot more mortar to bring up the rest of the lintels but it seems excessive amount of mortar to use as there will be approx 55mm gap to fill in at the lowest point. Any cheaper shim alternatives? Or should I just buy a bunch of metal steel plates. I can get 60 qty 100mm x 100mm x 3m mild steel plates for around £50



Lastly I had my planning permission approved last month which means I can build this to a 2.7m height which is great news! Was a simple process and cost me approx £300 for the submission and paying someone to do the drawings for me.

 

[Jesmona]

UPDATE #2

Forms builts, rebar tied in and dowels epoxy'd into the older slab

View attachment 169410View attachment 169411

Concrete poured, it was 150mm deep and took approx 3-4 hours by myself, I was definitely over thinking the process, hardest thing was remembering how many buckets of ballast I added to each mix

View attachment 169412View attachment 169415

Left the forms on for 72 hours and then removed.

View attachment 169413View attachment 169414

Now its time to start laying the concrete lintels these are 900mm long. I have a 40mm drop across the 5m length of the concrete base. This first lintel is the highest point so I thought I'd start from here and then pack up the rest with some sort of shim. Metal and slate shims are quite expensive and I need to make up quite a bit of height. Unsure whether to just use a lot more mortar to bring up the rest of the lintels but it seems excessive amount of mortar to use as there will be approx 55mm gap to fill in at the lowest point. Any cheaper shim alternatives? Or should I just buy a bunch of metal steel plates. I can get 60 qty 100mm x 100mm x 3m mild steel plates for around £50

View attachment 169416

Lastly I had my planning permission approved last month which means I can build this to a 2.7m height which is great news! Was a simple process and cost me approx £300 for the submission and paying someone to do the drawings for me.

Keep up the progress mate, good to watch and read along

 

[g8dy]

UPDATE #3

Lintels laid, had to use steel shims because the variation between highest and lowest point was 40mm, I didn't have enough shims to prop up all the lintels so just laid a few shims and then mortar on top to give it a bit of support. Cant see in the pic but I cut and laid DPC on each brick.

Floor frame made from c24 timber, doubled up the floor joists and coach bolted together, after this bit I added the DPC to the lintels.

m12 threaded rod, epoxy resin set into the concrete and then bolted and strapped around frame, did this 3 on each side.

75mm celotex fitted between joists and alu foil tape to seal the gaps. Also filled gaps with expanding foam.

Time to lay the floor, I went with 18mm shuttering plywood

sealed all edges.

Lessons learnt:

Should have just bought longer lintels instead of the shortest ones. That way less of them to lay and get level.

 

[Cabinetman]

Just a slight concern that you might get flex/movement between the edges of the ply flooring as it hasn’t got a t&g edge and doesn’t finish over a joist, I know it’s over celotex but it could deflect with equipment on it.
Probably easiest to fix afterwards now if there’s a problem by laying another layer OSB? Going the other way. Also OSB roofing sheets 2.4 x 0.6 come with a t&g edge.
Ian

 

[g8dy]

Just a slight concern that you might get flex/movement between the edges of the ply flooring as it hasn’t got a t&g edge and doesn’t finish over a joist, I know it’s over celotex but it could deflect with equipment on it.
Probably easiest to fix afterwards now if there’s a problem by laying another layer OSB? Going the other way. Also OSB roofing sheets 2.4 x 0.6 come with a t&g edge.
Ian

Hi Ian, the plywood sheets are all support at their ends on the joists. Do you mean the longest sides of the sheets should also be supported?

 

[Cabinetman]

Yes, fraid so

 

[Blister]

Looking good , We love a workshop / shed build.

 

[g8dy]

Yes, fraid so

Ill just have to make sure the heavy machinery is sitting on the joists as best as possible, or just lay an extra sheet when I get a mill/lathe in there. I'd like to avoid losing any height in the shed (its becoming more like a garden room/cabin now) another 18mm osb on top of what I have gets me that little bit closer to hitting my head on things.
The plan is to have a rail system on the ceiling to hold lights and cameras so I want as much clearance as possible.

T&G OSB looks great, I'll have to remember that for the next shed and its only about £10-15 extra per sheet, Im using 18mm Structural Plywood CE2.+

 

[Cabinetman]

You hopefully will be ok, just thought I ought to mention it. Enjoy your new workshop, the exciting time is fitting it all out.
Cameras?

 

[imageel]

A great start and looking good!
It's unclear what dims your joists are but given the bearers they are resting on I'd have thought you are good for ~400kg loading - my shed which is slightly larger @ 4x5m and with similar concrete support spans but 160mm deep joists has multiple 600Kg machines in it without problems so yours looks to be fine

 

[g8dy]

You hopefully will be ok, just thought I ought to mention it. Enjoy your new workshop, the exciting time is fitting it all out.
Cameras?

i run a small youtube channel and need the extra space filming and working on projects, that's the reason for building the shed. this build will also be in a video series on the channel too

A great start and looking good!
It's unclear what dims your joists are but given the bearers they are resting on I'd have thought you are good for ~400kg loading - my shed which is slightly larger @ 4x5m and with similar concrete support spans but 160mm deep joists has multiple 600Kg machines in it without problems so yours looks to be fine

Thanks for the reassurance. The floor, walls, and roof are all made from 4x2 C24 Timber.

 

[flying haggis]

Before you get too far along. I would have put dpc under the joists that are resting on the lintels.

 

[g8dy]

Before you get too far along. I would have put dpc under the joists that are resting on the lintels.

Yes, Ive place DPC under each lintel before adding the insulation

 

[Joe1975]

I used WBP plywood for extra piece of mind. Again all edges need to be supported. Seems a shame to have laid that much concrete and ended up with a suspended (I.e. springy) floor.

 

[Spearmint Wino]

Watching this thread with interest as I’m in the planning stages of a 5x3 workshop

 

[g8dy]

I used WBP plywood for extra piece of mind. Again all edges need to be supported. Seems a shame to have laid that much concrete and ended up with a suspended (I.e. springy) floor.

I haven't noticed any bounce while walking on the unsupported edges, if it gets bad I guess I can just lay some 12mm T&G flooring over the 18mm plywood.

Watching this thread with interest as I’m in the planning stages of a 5x3 workshop

Feel free to ask any questions

 

[Bensox]

Following with interest, thanks for all the photos. If you do need an extra flooring layer I can recommend concrete board - I've used this to replace rotten MDF flooring in my bathroom (STS No More Ply tongue and groove 18mm flooring). It is completely weatherproof and very sturdy, although you need a good stone-cutting or diamond blade to trim.

 

[g8dy]

UPDATE #4

Walls and roof framed and sheathed, this was a bit of a task getting this erected by myself. I'm glad I split the 5m wall into 2 sections because lifting it and moving it into position by myself would have been impossible.

I stupidly built the walls in the wrong order when stacking on top of one another so I had to move the frames off the flooring to get to the one I needed first. I didn't know what I was doing at this stage, not sure of the techniques to ensure the walls were plumb, I used a spirit level but the walls were definitely a few cm out of square which I realised when putting on the roof joists,

Here where I messed up (which you can read about in this separate thread here). I used the same 4x2 timbers to make my roof, adding to this, I run out of timber to space the roof joists 400mm and instead had to space them 500mm. The roof was a little bouncy because of this and because my pitch is only 2 degrees I was worried about snow and rain weight, plus I have no decided to add a skylight. By this point I have nailed all the joists in place and fix in the OSB sheets.

After hearing all the helpful comments in the other thread I decided to redo my roof using 6x2 joists. I cut of all the joists hangers and will be installing a few angle brackets. I'll also be adding 2 flitch beams with a 10mm thick steel plate either side of the skylight to further reinforce the roof.

Lots of rain this week so for now I just wanted to get everything covered, I added a breather membrane and just laid the OSB sheets on the joists so the water doesn't pool.

I will leave it like this until later in spring, Im currently waiting on PVC door and window to arrive, then ill recut the wall frame to accommodate these, still need to order the skylight and will then install the flitch beams and build the upstand.

Then goes on the EPDM roof, fascias & soffits. Internal wall insulation and OSB internals

Then the larch cladding (still need to order) and metal wall cladding (will be using the metal cladding on the back wall and wall against the fence to save some £££)

What started as a budget shed build has turned into a full-blown garden room, PVC windows, doors, skylight and cladding has massively added to the budget (almost doubled what I had planned to spend) but after we saw how big it was in relation to the overall garden we decided we wanted something that would like nice, hopefully add value to the house.