Garden Workshop (Block and Wood)

[Skavenger]

Hi;

I have finally started to build my garden workshop / shed and thought I would start a project thread to show what I am doing and get advice along the way.

The shed will be a part block / part wood frame construction with probably a fibreglass roof. The blocks will be about 4 layers high with a timber frame on top clad with T&G on the outside and possibly OSB or Ply on the inside to accommodate for fitting some celotex insulation.

Here is the original shed - not even tall enough to walk in without catching your head on something!!

First I dismantled the wooden sides, cut the roof pins holding on the roof and removed the corrugated asbestos roof sheets. Removed the rest of the timber frame - apart from one piece of what looks like a telegraph pole.

I then prepped the top of the rear wall by cutting of the concrete curved weather facia to facilitate extending the top two courses to accommodate the new roof flashings. Also dug out the existing lead flashings.

Also in the pic above I cleaned up the crack in the rear wall ready for a repair and removed the cement pattern blocks where I will fit probably fit a window.

All of the old wood has gone to the recycling centre and I just need to get rid of the 1 1/2 sheets of Corrugated Asbestos.

The new workshop will be higher (less than the allowed 2.5m) so I can easily walk into and work in it. The floor area is triangular and tapers from the left to the right as you look at it in the pics but I will extend it as far as is practicable and the remaining outside area to right of the shed will be a covered log / bin store.

As I mentioned earlier, the roof of the shed will probably be fibre glass but I either need to continue this to the right for the log store or maybe use a separate pitched lean to roof for the logs using tiles of felt? This would mean trying to some how join the two to prevent a dripping area between the lean to and the workshop?

Initially I was going to have a pitched tiled roof from rear to the front but this would have needed a gutter which would encroach on the path. So to help maintain head room my intention is to have a flat roof. The flat roof will have a water run off on the left maybe into a small water butt?

Questions:

1. Do I need to lay a first course of blocks on their sides?
2. Do I need a DPC?
3. Do I need any sort of membrane in the concrete floor construction?
4. Do I build the corners up first?
5. On a wall of 4 blocks high do I need any pillars?
6. For the door what gap should I leave?
7. When laying the wall blocks what spacing between the breeze blocks?
8. What would anyone recommend for a door and windows? Needs to be low cost but long lasting?
9. What depth do I need to consider for the flat roof? I need this to work out measurements from where I intend the flashings to be installed between the top two courses of blocks (those painted cream in the pic above). This will help me to work out how far down I need to go to maintain head room.

More to follow...........

 

[Mr Chibs]

Think you've got too many questions to answer, and I suppose it depends if you are doing this 'by the book' or 'home brew'

Should have some type of footings, even if it's 4 courses tall.
DPC yes, membrane, insulation yes... but if it's for storing golf clubs etc perhaps this is all overkill and needless expense.

How deep are the footings for the current 'wall' where intend to put the window?

Why not just sort out a decent base, then make a wooden shed to the size you want?

I take it you will adding two courses of blocks to the wall, to the left of the cream wall?

 

[Skavenger]

Think you've got too many questions to answer, and I suppose it depends if you are doing this 'by the book' or 'home brew'

Should have some type of footings, even if it's 4 courses tall.
DPC yes, membrane, insulation yes... but if it's for storing golf clubs etc perhaps this is all overkill and needless expense.

How deep are the footings for the current 'wall' where intend to put the window?

Why not just sort out a decent base, then make a wooden shed to the size you want?

I take it you will adding two courses of blocks to the wall, to the left of the cream wall?

The workshop will be my dirty workshop (engine tinkering, metal fabrication etc) and needs to be water / damp proof as it will be where I situate my compressor and welding gear. There will be a work bench / vice etc up against the back wall.

The wall to the left is about two courses too high as I was only intending to have block walls all around about three courses high with a timber frame mounted on top. But it seems a waste to knock off the two top layers. To make the structure even I may make the wood cladding the same height all the way around so a few courses of the LH wall would be covered (aesthetics only).

I have just started to excavate to ID the existing footings and will post back.

Didn't want a wooden shed, there is not a lot of room and the space lost by mounting a wooden shed in front of the garden wall would be better used as workspace hence my decision for a part block / part wooden structure.

 

[Mr Chibs]

One of our local tips will take asbestos sheeting, you have to get 'their' bags first... FOC, bag it then take it.

I guess you want to make this as cost-effective as possible?
Is the cream wall yours?
Why not bring your new wall up to this level, and wood from there?
Doubt you'd need pillars, you could always strap together, again thought depends on the top half.

Keep us posted.

 

[Skavenger]

Well I did the preliminary excavations and it's not looking good
The footings for the back wall are not very deep at all and I am not sure how they have been constructed. Looks like the first layer has just been surrounded with concrete?

In the pic above the level of the earth is about where I want the new floor level!!
In the next pic the earth is at the same level as in the previous pic and is about the same level as the path.

The reason I want the floor at this level is because I intended to put the roof flashing in between the top block layer and the one below it. I could try and come up with another way of sealing the roof where it meets the wall but I am at a loss at the moment.

I could cut a groove half way down one of the blocks or found some way of attaching it to the top?

 

[Mr Chibs]

Think the flashings are the least of your worries at the moment.

It looks like the blocks have been laid straight on the earth and a footing (kind of) poured around them.
It's also made more complex as you want to lower the floor level.

I take it a complete tear-down is not an option?

Could you not put a dpm sheet down, pour concrete slab to just above current 'footing' yes the floor level is higher, but this may help with damp and might help keep everything together.
Get some decent straps... (like meccano brackets) to secure pillar to wall, build up side wall and new front wall in block.
Then use wooden stud-work attached to inside of walls to make top half and angled roof, insulate outside walls (will be resting on your blocks) then clad with wood etc.

Yes it will be shed like, but could work with what you have.

I still think I'd be tempted to just build and insulated shed, on a new concrete base, it will be dry and you can make it as large as you want.

 

[Skavenger]

A tricky task but what about underpinning?

 

[Mr Chibs]

Is it worth the effort?
It would be more complex than just rebuilding the bits of the walls. You'd have to do in sections...
As for the long wall, I presume you share this with your neighbour? So perhaps, you couldn't just 'do it'

If you started again, you could make your footings for the 3 sides, DPC, you could even lay the blocks down, so it's double thickness and start from scratch, that way you know 3 sides will be good and strong.

What say you?

 

[Skavenger]

Is it worth the effort?
It would be more complex than just rebuilding the bits of the walls. You'd have to do in sections...
As for the long wall, I presume you share this with your neighbour? So perhaps, you couldn't just 'do it'

If you started again, you could make your footings for the 3 sides, DPC, you could even lay the blocks down, so it's double thickness and start from scratch, that way you know 3 sides will be good and strong.

What say you?

It's my wall but if I start dismantling it the missus will throw an eppi!!

I need to check the height and do some maths e.g. depth of roof, location of roof fixing etc. Then I can work out what level the floor could be and you never know with luck I may be able to raise it??

 

[Skavenger]

OK so a little more progress today. Decided to excavate under the footings, with the idea of underpinning them, doing it in stages to maintain some support.

Dug out one corner far enough back and deep enough to get a breeze block in place. I have excavated under the existing footing but only partially as far back as the blockwork on top.

Banged in some concrete high enough so that a block will just fit on top and leveled it.

I dug another channel on the right hand side leaving the center in place. It started raining so I covered everything up.

Next I will cement in a couple of blocks onto the concrete that I have just laid and then fill in with concrete.
My plan is not to underpin the whole wall the same but in pillars. The piece in between will be dug out but not as deep and be filled with concrete to strengthen it all up.
Once the back wall footings have been done and the floor is in I will tidy up and render over the old rear footing down to the floor making a step at the back of the workshop space. This will mostly be under a workbench. It's a pain not to have a nice neat flat area but I have to work with what I can.

I am considering doing something similar with the LH wall but am leaning on removing it all together and starting from scratch because it has not been tied to the rear wall properly. I will need to hire a breaker to smash up the footings? If I do rebuild my front three walls will be as I want them and sound.

Oh before I started this morning I was met by this fella:

 

[Mr Chibs]

Is the side wall loose? if so nuke it and start again.

Keep us posted with pics.
When you attach, insert as thumbnail, then you pics won't take up the whole screen.

 

[Skavenger]

The side wall is not loose but anything can be demolished. It does not look as if it is fixed to the back wall as a gap has appeared and the ivy has found its way through. The problem with this wall is that it is retaining a lot of earth on the other side. I would need to clear some of it to be able to get to the other side or just build it with the earth in place an not worry about how it looks!!

 

[Mr Chibs]

Depends how much work you want!

If the wall seems strong, perhaps you can secure it with some straps.

I used some polyester resin to fix some rise and fall guttering brackets, can't believe how strong the bond is when it sets... it really is like rock!
You could probably get rid of the ivy and fill the gap with resin about a tenner a tube.
If you then build a third wall opposite the big one, it will strengthen it all up.

 

[Skavenger]

Bit more prepping to underpin the wall - there is allsorts buried in here!!

So a bit of angle grinder work to cut some metal then some Disc Cutter work to trim the underside of the existing footing to fit the block work.

Then once it was all leveled I banged in some mortar to fix the the block for my underpinning pillars in place:

Tomorrow I'll dig the footings for the two block walls and mix up some concrete, some for the footings and some around my pillars.

My plan is to concrete in the wall footings and then the following day dig out the floor hammer in the hardcore and then concrete the floor. When the floor is concreted the facia of the pillars and existing wall footings will also be concreted.

Then i'll build up the corners and first course of the walls and then scree coat the floor?

Does this sound sensible?

 

[Skavenger]

So today I started on the wall footings:

The blocks that were there were laid on the path with not a lot of mortar - they came off without much of a struggle.
I decided to take a measurement from the garage wall which is to the left in the pic above, with the intention that the new shed wall would be in the same location as the blocks that I had just removed.
I worked out how wide the path should be and measured 89cm from the garage wall then made marks down the path and joined them up.
The pin line is 20cm from the chalk line (the width of my footings).

I then cut through the path with a Disc cutter and started to dig out the footing.

To get the correct depth I decided to work of the side wall by the steps. I wanted to ensure that with 200mm deep concrete footing a block place on top woould line up with the blocks in the existing wall. This would make tieing them together and getting them the same height easier.

All leveled up with a spirit level.

So far I have filled nearly 4 large builders bags (about 800 - 900kg each). Looking at what is left in the middle I need to dig out 250mm (just above the depth of the wall footings) I reckon that could be another 4 bags!!
I haven't managed to get rid of the soil I have already removed so I think I am going to have to pay a contractor

When I put the concrete in should I board the inside edge?