Asgard Bicycle Shed Concrete Slab

[Narthecius]

Hello everyone. I have started the preparation to lay a concrete slab in my front garden for a steel Asgard bicycle shed. I've never done anything like this before, but have researched extensively on here (thank you) and YouTube etc. Does my plan look ok? Many thanks in advance.

Objective:
Lay 2400 x 1250 x 100mm concrete slab in front garden, Back of slab will (ideally) be laid adjacent to garden wall pillar, leaving a ~10cm gap behind the slab to the garden wall (illustrated in photos). Slab will sit proud of block paving by 20mm.

Plan:
Remove shrub roots
Continue to excavate to 190mm depth
Build shuttering
Rent whacker, cement mixer and concrete float
Lay 100mm MOT Type 1 and whack down
Lay 10mm Blinding Sand and whack down
Fit DPM
Cut & fit rebar and spacers
Mix, pour and level 100mm C25 concrete
Wait 1 hour and float concrete
Wait 24-48 hours and remove shuttering
Make good block paving

Questions:
Is it sensible to build the slab right up to the garden wall pillar? If it is, do I just expose the footings and try and pour around them (obviously will make shuttering a bit more difficult). If it’s not, I will just bring the whole thing forward another 100mm to leave a gap between the pillar and the slab.

Is it ok to leave a 100mm (or more) gap between the slab and the rest of the garden wall? If so, do I fill it with shingle or something similar?

Is it a good idea to have the slab sitting 20mm proud of the block paving and rest of garden?

 

[noseall]

Is it sensible to build the slab right up to the garden wall pillar? If it is, do I just expose the footings and try and pour around them (obviously will make shuttering a bit more difficult). If it’s not, I will just bring the whole thing forward another 100mm to leave a gap between the pillar and the slab.

Yes. Try and eliminate any weed growth hotspots.

Is it ok to leave a 100mm (or more) gap between the slab and the rest of the garden wall? If so, do I fill it with shingle or something similar

Concrete it.

Is it a good idea to have the slab sitting 20mm proud of the block paving and rest of garden?

For what purpose?

Have you checked to see if you need PP?

 

[Narthecius]

Thank you for your reply @noseall.

Regarding the gap at the back. If I’m to concrete it, should this be a separate job to pouring the slab? Or should I just pour the slab all the way up to the wall/column (e.g have 3 sides of shuttering & the wall/column as the 4th)?

I was going to sit it up 20mm from the block paving because the shed base is a flat piece of steel. Although it’s painted with a strong finish, I worry about it sitting in water. Maybe I’m overthinking?

Planning permission is an odd one. My local borough has indicated they will not require planning permission for bicycle sheds in front gardens, but that doesn’t explicitly mean they can’t enforce. I think they’ve left it grey so they can still pursue monstrosities.

 

[noseall]

Regarding the gap at the back. If I’m to concrete it, should this be a separate job to pouring the slab? Or should I just pour the slab all the way up to the wall/column (e.g have 3 sides of shuttering & the wall/column as the 4th)?

Pour right up to wall etc. Why encourage a future garden of Eden for weeds?

I was going to sit it up 20mm from the block paving because the shed base is a flat piece of steel. Although it’s painted with a strong finish, I worry about it sitting in water. Maybe I’m overthinking?

If it's effectively an outdoors bit of kit, it should be weather tolerant....? There will always be a degree of moisture with outdoors stuff, especially if it's metal.

Planning permission is an odd one. My local borough has indicated they will not require planning permission for bicycle sheds in front gardens

 

[Odds]

Weeds always find a way. Best you can do is limit the growth and maintain the area with a weedkiller of choice.

 

[Narthecius]

@noseall thank you, I really appreciate it. I’ll put up some pictures when I’m finished.

@Odds don’t they just! I’m considering leaving a slightly larger gap than I had originally planned for behind the shed. This way I should have better access to remove weeds.

 

[stevie888]

One step you've missed is curing: this is vital for god quality concrete. Get polythene over it as soon as you can and ideally keep it watered for a few days.

Don't make the concrete too wet: this will make it easier to spread out for sure but at the expense of weakening it and make it harder to finish

 

[securespark]

this is vital for god quality concrete.

But you don't want a holy finish....

But seriously, I laid an extension to my original 1960 concrete driveway and didn't cover it well with polythene and let it go off slowly. The surface is now friable and bits break off.

 

[Narthecius]

Thank you chaps, I will definitely do this. I’m not in a huge rush, other than a bit of pressure because the shed is currently in pieces… in the hall!

I’m currently digging up this tree stump, which is proving to be an emotional experience.

 

[Narthecius]

I’ve removed the tree and almost all of the roots. I was left with 4 very stubborn, deep roots. I’ve cut them as short as I can. The shallowest one (closest to the tape measure) would be underneath the MOT and is around an inch in diameter.

Am I ok to crack on backfilling or do I need to excavate further (please say no!).

 

[Narthecius]

Nearly finished now. Just need to sort out the block paving. I think I’m going to put some sand down, lay a mortar haunch against the DPM and set the blocks in. There will be a small gap till fill, I guess with mortar as well? Thank you, everyone!

 

[Notch7]

I would put some nice tall plants around it quickly.........I hate to mention planning permission

 

[Narthecius]

I would put some nice tall plants around it quickly.........I hate to mention planning permission

My local authority, although retaining the right to enforce, have indicated they are happy for bicycle storage sheds in front gardens. Lots of my neighbours have them too. But you’re right, I will remove the ivy in the corner and plant something nice and tall!