New Shed Build

West Cork Paul

West Cork Paul

Man in a Shed
Subscriber
For your delight and amusement over the coming months I will chronicle my new shed build here. Also by doing so I hope that anyone who actually builds things for a living, and there are plenty of you on here, will chip in with constructive (😂 see what I did there) suggestions as to how to build it. It will save me having to pay for any professional advice. In return you get to laugh as I fuck it up for measuring and cutting wood is, I know from experience, the one thing I just can’t seem to get right.

The shed in question is ‘The Shed’, the one with the famous roof. The roof is fine, a bit of tree detritus on it but otherwise it’s in fine shape, hasn’t let a drop of water in. The problem is the sides of the shed are rotting away.

IMG_3205.webp


IMG_3204.webp


You may be asking yourself ‘ why not just buy a kit shed?’. Well, I want to fill the space available now the bushes have all been cut back and it’s not square, it’s trapezoid. Plus I want to mate it up to the workshop next to it so I’m maximising the floor space available to me. Also, it’s going to become an office and store room so I can move all the paperwork that running a business generates out of the workshop and somewhere else, plus I can store all the multiple volumetric metres cubed of service consumables which occupy at least 1/4 of my workshop space. Plus I’m going to insulate it and then I’ll have somewhere warm to hide in the winter.

The first thing, once the current shed is removed, is to frame the floor. I don’t really want to pour a concrete slab as I’ve got enough issues with water run off that area since the slab for the workshop shed was laid. Thus, I’m thinking of using screw piles. I’m going into rock once I get a couple of inches down so recognise I’ll have to drill a hole for each pile. I just think it will be easier and cheaper than laying a slab apart from the water diversion issues.

Measurements are approximate at this stage on this sketch but I think this is what I need to do.

IMG_3207.webp


I’ve checked span tables but am a little confused by them as they may seem to go up to 125kg/sq.mtr (1.25kN/M2). The confusion lies in whether that’s the dead load on the floor placed on the joists, which seems ridiculously low, or the dead load on the top surface area of the joist itself. I’m guessing the latter but would rather not guess.

Once the floor frame is down how do I insulate between the joists and what thickness insulation? Would 75mm suffice in the floor? What do I use to suspend and hold the insulation ?

Ok, laugh away
 
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Seems a bit elaborate to me Paul. If you're on solid rock then as long as you can achieve some sort of foundation on a level site I'd just build three strip pads out of 9" concrete blocks laid flat, across the width of the shed, one at each end and one in the middle and put 6x2 joists straight onto those without the need for the heavy beams and piles, which will be expensive and raise your floor level significntly.

If the pads are built to the exact size of the floor frame, when you clad the walls the cladding can extend over the face of the blocks and keep them dry. Though I'd still put a strip of dpc under the joist where they sit on the blockwork.
Given the small size I'd prefabricate the floor as a solid panel and use it as a template to lay out your blockwork.

50 mm of insulation should be enough under the floor. You lose most heat through the roof and the walls. 4x2 floor joists would be plenty strong enough but 6x2 gives you more room for insulation as ideally you should have a ply base under the insulation as rodents love to chew it. If you premade a floor panel in that way I'd run a tile batten along the joists so that the ply (6mm) backing and insulation bats sit on top with the insulation finishing flush with top of the joists. The treat the whole floor panel including the play with wood preserver before fixing it down and fitting the insulation.

And on the subject of rodents, the main disadvantage of building off the ground, whether on masonry pads or screw piles, is rodents and other critters will move into the void underneath.
 
My advice to anyone building a shed would be to build twice as big as you think necessary and then add a bit.

I like the raised platform But you will need to lower the area beneath the shed or increase the height of the ground at the front to make for ease of entry.
 
If you're looking for comfort a log cabin may be worth exploring, they are easier to put up and can be customised to suit what you need. However, the West Cork spec footprint may make it a bit more expensive 🤔😂
 
West Cork Paul said:
For your delight and amusement over the coming months I will chronicle my new shed build here. Also by doing so I hope that anyone who actually builds things for a living, and there are plenty of you on here, will chip in with constructive (😂 see what I did there) suggestions as to how to build it. It will save me having to pay for any professional advice. In return you get to laugh as I fuck it up for measuring and cutting wood is, I know from experience, the one thing I just can’t seem to get right.

The shed in question is ‘The Shed’, the one with the famous roof. The roof is fine, a bit of tree detritus on it but otherwise it’s in fine shape, hasn’t let a drop of water in. The problem is the sides of the shed are rotting away.

View attachment 153592

View attachment 153593

You may be asking yourself ‘ why not just buy a kit shed?’. Well, I want to fill the space available now the bushes have all been cut back and it’s not square, it’s trapezoid. Plus I want to mate it up to the workshop next to it so I’m maximising the floor space available to me. Also, it’s going to become an office and store room so I can move all the paperwork that running a business generates out of the workshop and somewhere else, plus I can store all the multiple volumetric metres cubed of service consumables which occupy at least 1/4 of my workshop space. Plus I’m going to insulate it and then I’ll have somewhere warm to hide in the winter.

The first thing, once the current shed is removed, is to frame the floor. I don’t really want to pour a concrete slab as I’ve got enough issues with water run off that area since the slab for the workshop shed was laid. Thus, I’m thinking of using screw piles. I’m going into rock once I get a couple of inches down so recognise I’ll have to drill a hole for each pile. I just think it will be easier and cheaper than laying a slab apart from the water diversion issues.

Measurements are approximate at this stage on this sketch but I think this is what I need to do.

I’ve checked span tables but am a little confused by them as they may seem to go up to 125kg/sq.mtr (1.25kN/M2). The confusion lies in whether that’s the dead load on the floor placed on the joists, which seems ridiculously low, or the dead load on the top surface area of the joist itself. I’m guessing the latter but would rather not guess.

Once the floor frame is down how do I insulate between the joists and what thickness insulation? Would 75mm suffice in the floor? What do I use to suspend and hold the insulation ?

Ok, laugh away
Click to expand...
OMG, Christmas coming in early, Paul’s new shed build thread, so no competition , this will turn out to be the winner of thread of the year😇🤷🏻‍♂️😎😆, so exciting😆😆😆
 
Paul, here another alternative method, very easy for beginner sheds, make a base from sleepers, flat completely following your outlined floor plan, supported by concrete slab, block pile, or even slabs.

Make sip panels easy to handle on your own, framing made with 5x2 100mm kingspan in it, clad with 11mm osb both sides,
Erect, screw on top of sleeper base, then breather membrane , batten on top, then cladding of choice , cladding running down covering your sleeper base too, you can sip panel the lot, floor, walls and roof, super strong and so easy to create odd shape buildings, use 100mm insulation or more for all of it, use a prefab door frame bolted in with prefab doors which you can clad with same material👍
 
Gimlet said:
Seems a bit elaborate to me Paul. If you're on solid rock then as long as you can achieve some sort of foundation on a level site I'd just build three strip pads out of 9" concrete blocks laid flat, across the width of the shed, one at each end and one in the middle and put 6x2 joists straight onto those without the need for the heavy beams and piles, which will be expensive and raise your floor level significntly.

If the pads are built to the exact size of the floor frame, when you clad the walls the cladding can extend over the face of the blocks and keep them dry. Though I'd still put a strip of dpc under the joist where they sit on the blockwork.
Given the small size I'd prefabricate the floor as a solid panel and use it as a template to lay out your blockwork.

50 mm of insulation should be enough under the floor. You lose most heat through the roof and the walls. 4x2 floor joists would be plenty strong enough but 6x2 gives you more room for insulation as ideally you should have a ply base under the insulation as rodents love to chew it. If you premade a floor panel in that way I'd run a tile batten along the joists so that the ply (6mm) backing and insulation bats sit on top with the insulation finishing flush with top of the joists. The treat the whole floor panel including the play with wood preserver before fixing it down and fitting the insulation.

And on the subject of rodents, the main disadvantage of building off the ground, whether on masonry pads or screw piles, is rodents and other critters will move into the void underneath.
Click to expand...
What he said 👆... if you have rock that close to the surface take advantage of it ... if you need any advice on bracing the walls for strength just go look at your gates and do it the opposite way to them to actually strengthen your structure 👀😆
 
West Cork Paul said:
For your delight and amusement over the coming months I will chronicle my new shed build here. Also by doing so I hope that anyone who actually builds things for a living, and there are plenty of you on here, will chip in with constructive (😂 see what I did there) suggestions as to how to build it. It will save me having to pay for any professional advice. In return you get to laugh as I fuck it up for measuring and cutting wood is, I know from experience, the one thing I just can’t seem to get right.

The shed in question is ‘The Shed’, the one with the famous roof. The roof is fine, a bit of tree detritus on it but otherwise it’s in fine shape, hasn’t let a drop of water in. The problem is the sides of the shed are rotting away.

View attachment 153592

View attachment 153593

You may be asking yourself ‘ why not just buy a kit shed?’. Well, I want to fill the space available now the bushes have all been cut back and it’s not square, it’s trapezoid. Plus I want to mate it up to the workshop next to it so I’m maximising the floor space available to me. Also, it’s going to become an office and store room so I can move all the paperwork that running a business generates out of the workshop and somewhere else, plus I can store all the multiple volumetric metres cubed of service consumables which occupy at least 1/4 of my workshop space. Plus I’m going to insulate it and then I’ll have somewhere warm to hide in the winter.

The first thing, once the current shed is removed, is to frame the floor. I don’t really want to pour a concrete slab as I’ve got enough issues with water run off that area since the slab for the workshop shed was laid. Thus, I’m thinking of using screw piles. I’m going into rock once I get a couple of inches down so recognise I’ll have to drill a hole for each pile. I just think it will be easier and cheaper than laying a slab apart from the water diversion issues.

Measurements are approximate at this stage on this sketch but I think this is what I need to do.

I’ve checked span tables but am a little confused by them as they may seem to go up to 125kg/sq.mtr (1.25kN/M2). The confusion lies in whether that’s the dead load on the floor placed on the joists, which seems ridiculously low, or the dead load on the top surface area of the joist itself. I’m guessing the latter but would rather not guess.

Once the floor frame is down how do I insulate between the joists and what thickness insulation? Would 75mm suffice in the floor? What do I use to suspend and hold the insulation ?

Ok, laugh away
Click to expand...
Is that really the same shed as these pictures below are after the last refurb 🤔

IMG_7340.webp


IMG_7339.webp
 
Gimlet said:
Seems a bit elaborate to me Paul. If you're on solid rock then as long as you can achieve some sort of foundation on a level site I'd just build three strip pads out of 9" concrete blocks laid flat, across the width of the shed, one at each end and one in the middle and put 6x2 joists straight onto those without the need for the heavy beams and piles, which will be expensive and raise your floor level significntly.

If the pads are built to the exact size of the floor frame, when you clad the walls the cladding can extend over the face of the blocks and keep them dry. Though I'd still put a strip of dpc under the joist where they sit on the blockwork.
Given the small size I'd prefabricate the floor as a solid panel and use it as a template to lay out your blockwork.

50 mm of insulation should be enough under the floor. You lose most heat through the roof and the walls. 4x2 floor joists would be plenty strong enough but 6x2 gives you more room for insulation as ideally you should have a ply base under the insulation as rodents love to chew it. If you premade a floor panel in that way I'd run a tile batten along the joists so that the ply (6mm) backing and insulation bats sit on top with the insulation finishing flush with top of the joists. The treat the whole floor panel including the play with wood preserver before fixing it down and fitting the insulation.

And on the subject of rodents, the main disadvantage of building off the ground, whether on masonry pads or screw piles, is rodents and other critters will move into the void underneath.
Click to expand...

Thank you, and some good ideas.

If I understand correctly I use the concrete blocks as the foundations? But how do I fix the joists to the blocks? The same way I put my sill plate or whatever it’s called onto the concrete slab for the workshop shed, ie with those hammer in frame fixing thingies? That’s fine for the slab as it weighs XXXX tonnes but how would I anchor the concrete blocks to the ground? Mind you the current shed hasn’t blown away and it’s just sitting on paving slabs.
 
Fight the streets Fmd said:
Paul, here another alternative method, very easy for beginner sheds, make a base from sleepers, flat completely following your outlined floor plan, supported by concrete slab, block pile, or even slabs.

Make sip panels easy to handle on your own, framing made with 5x2 100mm kingspan in it, clad with 11mm osb both sides,
Erect, screw on top of sleeper base, then breather membrane , batten on top, then cladding of choice , cladding running down covering your sleeper base too, you can sip panel the lot, floor, walls and roof, super strong and so easy to create odd shape buildings, use 100mm insulation or more for all of it, use a prefab door frame bolted in with prefab doors which you can clad with same material👍
Click to expand...

I thought about doing the whole thing with SIPs but as they only seem to come in standard sizes I don’t think they will work for this space.

Plus I have to be realistic, it’s just me, there’s no young muscle to assist in the heavy lifting. I can lift an 8x4 piece of osb or ply but I won’t be able to lift, manoeuvre, support and fix 2 bits of osb with insulation sandwiched in between and a frame running round the edge of 5x2, it will just be too heavy.

I like the idea of the sleepers but think I’ll use concrete blocks as I worked with railway sleepers once before and they’re buggers to cut through unless I get the chainsaw on them.

I like the ideas suggested of making up the floor pan and laying it down on the sleepers/blocks but again weight is a consideration so I think I’ll lay out the blocks (or sleepers), cut some 18mm OSB sheets to size, lay a DP membrane over the blocks/sleepers, lay the OSB sheets down, fix some 4x2 framing/joists on top of the base sheets, fill the voids with insulation panels, then lay more OSB on top and that’s the floor done.

Now, 600mm or 400mm centres for the joists? 400 I guess.
Also 18mm or 12mm OSB?

Also, I guess I’ll have to get a mini digger in to scrape off the top 2 inches and get down to rock.

What’s the best way to level the concrete blocks or sleepers? Do I need to get a mixer and make up some concrete to pad out under the blocks?

I am glad I threw this out there though - thank you all.
 
West Cork Paul said:
Thank you, and some good ideas.

If I understand correctly I use the concrete blocks as the foundations? But how do I fix the joists to the blocks? The same way I put my sill plate or whatever it’s called onto the concrete slab for the workshop shed, ie with those hammer in frame fixing thingies? That’s fine for the slab as it weighs XXXX tonnes but how would I anchor the concrete blocks to the ground? Mind you the current shed hasn’t blown away and it’s just sitting on paving slabs.
Click to expand...
If you got any sort of foundation you don't need to anchor the blocks to the ground. But if your instinct is to over-engineer (mine is) you could set a couple of rebars into the concrete/rock and build the blocks around them. Given the apparently sheltered position of the shed and the fact the last one hasn't blown down in the 150 years since you built it out of old skirting board, I wouldn't bother.

To anchor the shed to the blocks I'd use 1" x 1/4" galvanised restraint straps, like you'd use to secure a roof structure to walls. You can buy straight ones. Just run them a good couple of feet up the stud frame and down the side of the blockwork to the foundation and screw them sideways into the blockwork before cladding over them. Much stronger than bolting vertically down through floor or timbers into the top of the blocks. That'll easily crack out under lateral load (high wind). Fixing horizontally into the blocks from the side they never will.
 
West Cork Paul said:
I thought about doing the whole thing with SIPs but as they only seem to come in standard sizes I don’t think they will work for this space.

Plus I have to be realistic, it’s just me, there’s no young muscle to assist in the heavy lifting. I can lift an 8x4 piece of osb or ply but I won’t be able to lift, manoeuvre, support and fix 2 bits of osb with insulation sandwiched in between and a frame running round the edge of 5x2, it will just be too heavy.

I like the idea of the sleepers but think I’ll use concrete blocks as I worked with railway sleepers once before and they’re buggers to cut through unless I get the chainsaw on them.

I like the ideas suggested of making up the floor pan and laying it down on the sleepers/blocks but again weight is a consideration so I think I’ll lay out the blocks (or sleepers), cut some 18mm OSB sheets to size, lay a DP membrane over the blocks/sleepers, lay the OSB sheets down, fix some 4x2 framing/joists on top of the base sheets, fill the voids with insulation panels, then lay more OSB on top and that’s the floor done.

Now, 600mm or 400mm centres for the joists? 400 I guess.
Also 18mm or 12mm OSB?

Also, I guess I’ll have to get a mini digger in to scrape off the top 2 inches and get down to rock.

What’s the best way to level the concrete blocks or sleepers? Do I need to get a mixer and make up some concrete to pad out under the blocks?

I am glad I threw this out there though - thank you all.
Click to expand...
Use mortar to bed and Level the blocks and unless you live on a diet of mushy peas and beans and just happen to be
Stood next to the 9th wonder of the world, I wouldn’t worry about it, I doubt you’ll get natural winds strong enough to move it
 
Hugo Magnus said:
I like the raised platform But you will need to lower the area beneath the shed or increase the height of the ground at the front to make for ease of entry.
Click to expand...

Steps, Hugo, steps. I’ll build a step or two to get up there. I plan on having a porch across the front of it where I can sit on my rocking chair, tartan blanket across my lap, shotgun by my side, bottle of potín in hand, gently rocking back and forth to while away my days.

IMG_3216.webp
 
For the floor you definitely need 18mm on the top but I used WBP ply for mine. Much nicer finish than OSB for a floor.
I used 12mm OSB internally on the walls though. The two external walls that weren’t seen on my workshop I used WBP again and also the roof which I covered in EDPM.
 
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