New workshop for 2020

[Sheptonphil]

Well, the time has come to embark on the new workshop build.

I have been for pre-planning and have been advised that I have a very high chance of acceptance, he could see no reason to refuse permission based on their criteria.

It will be built from the side of my house into the dead space on pic 1, and measure 3.9m x 7.2m opening with 2.5m wall to south.JPG

Can I ask advice re foundation/floor? pic 2 is what I am proposing.

I have a 2.5m wall to the front I can get tonne bags of type1 and sand placed over, within 3m of the build site. I cannot get concrete delivered without either a pump at £600 or taking down a metre of wall.
Will this method give a solid floor for the wood workshop. The workshop build will be timber frame, fire grade plasterboard inside, rockwool insulation and Hardie Plank clad, with the membranes and gaps as per Mikes 'how to build a shed'. Roof will be Marley cement slates to match house and garage.

 

[MikeG.]

Well, it's a risk. You might be OK, but it's unorthodox, and not what I'd do. You've also got a bit of an issue with thrust from compaction of the Type 1, with your external block wall as risk. I have seen masonry pushed over by stuff being compacted within it, and you are very vulnerable to that. Your plinth is essentially a retaining wall in this situation.

Are you trying to avoid digging? And yet you're proposing trench fill foundations....... You really have me a little puzzled. You don't appear to have any coursing in the masonry to level the Type 1 to, and yet that it what determines whether of not your floor is flat and level.

Puzzled, I am.

 

[Sheptonphil]

Thanks for the comments Mike.

I take your point about it now being a retaining wall in essence.

Using brick courses (Engineering?) instead of blocks Is not a problem for levels but still acts as a retainer though.

No trying to avoid digging as such, just trying to have a solid floor rather than suspended without concrete if possible

Would it be possible to use this method of compaction with a different wall construction? Two courses blocks flat Up to where type1 is, then a course of brick? Although I think it would make blocks proud around base.

I guess the celotex doesn’t compress when boarded over, so should be a solid floor.

I’m not going to commit until you think it’s a viable build method.

Thanks

Phil

 

[Fil]

What reason do you need planning permission for? As 3.9 x 7.2m is under the 30meter allowance, and seems your going down the fire proof materials route?

Only asking as going 3.6 x 7 myself. Fire rated paint internal and Hardie or cereal cladding, hopefully.

 

[Sheptonphil]

Two reasons for planning, the first is our estate in built on Duchy of Cornwall land, there is a clause in the original planning in 1997 that all ‘permitted development’ rights have been stripped, in perpetuity, this was the first point made by the planning officer on Friday. There is to be no buildings of any sort without planning (or changing windows for UPVC without planning). Some of the covenants expired after 10 years, there are a lot that are still active. No commercial vehicles over 15cwt on the estate overnight, no caravans, no campers, no boats. Even on your own driveway.

Secondly, to use the cement slates I need at least 18.5 degree slope on roof. I’m going for 20 degrees. With the eaves at 2.4metres, the height to ridge of roof will be 3.5 metres so would have needed permission anyway as maximum even had I been able to use permitted development is 2.5 metre max height when 1 metre or less from boundary. Planning says if I were to use the metal sheets that kind of look like tiles, planning would be refused due to the visual impact the roof would make. If it’s done with the Marley tiles, there will be no problem.

The fireproof materials are because it is within 1 metre of a boundary fence, the wall on that side must be ‘predominantly non-combustable’ to comply with building regs. I have to have the building notice signed off.

 

[MikeG.]

What reason do you need planning permission for? As 3.9 x 7.2m is under the 30meter allowance.......

You're confusing two separate issues. There is no 30 sq m rule with regards to Planning Permission/ Permitted Developments Rights. The only floor-area limit there is that you don't exceed 50% of the land in total around the original house. That's a cumulative figure, so 3 or 4 smaller outbuildings totalled up could mean you can't build any more (and it includes extensions to the house). The 30 square metre thing is for Building Control (ie the threshold at which Building Regulations begin to apply).

 

[MikeG.]

..... just trying to have a solid floor...without concrete.......

Why?

 

[Sheptonphil]

..... just trying to have a solid floor...without concrete.......

Why?

Hi Mike

Solid as a shed this size really should have a sold floor not suspended (I believe) and no concrete only because a premix lorry cant access site without an expensive pump or me taking down part of the front wall.

Looks like concrete is the way you're advocating, if so is it viable to mix concrete for this floor 28sqm from tonne dumpy bags? I thought it may be too large an area to do with a mixer and barrow on my own. 3.7 m3 if my calculations are somewhere near.

thanks for help
Phil

 

[Blackswanwood]

If access is an issue block and beam may be worth considering?

 

[MikeG.]

The thing is, your footings need to be concrete anyway. There will be a fair amount of concrete in them. Line up 3 barrows, and get a couple of mates over. Or hire a dumper and make a crude chute to feed it.

 

[Sheptonphil]

The thing is, your footings need to be concrete anyway. There will be a fair amount of concrete in them. Line up 3 barrows, and get a couple of mates over. Or hire a dumper and make a crude chute to feed it.

I figured I could mix for the footings, and do in stages. I will try another couple of companies to see if they have a vehicle that can discharge over a 2.1m wall. There is a further 500mm drop the other side so the site is 2.6m down from the wall top. Taking a bit off the top of the wall may be the answer to go concrete, although the block and beam could be worth also looking at.

More research now, compacted type1 now off the table.

 

[Inspector]

Don't your concrete pumper trucks have booms to hold the hose/pipe above the ground? Here they routinely park on the street and are able to pump to all corners of the property. With you having a relatively mild climate not needing to go deep for frost, can't you pour a slab and footing/thickened edge in one go? Just asking. :?:

Pete

 

[MikeG.]

Don't your concrete pumper trucks have booms to hold the hose/pipe above the ground?........

Our OP is trying to avoid hiring a pump, which is fair enough, because they cost a fortune. It also requires two large vehicles (the concrete mixer and the pump lorry), and with our confined streets and small plots that can be a real headache.

An idea of the site layout would be handy.

 

[MikeG.]

....... 3.7 m3 if my calculations are somewhere near.......

I see you're allowing for 125mm thick concrete. With your slab size that's your bare minimum. Ideally it would be at least 25mm thicker. Are there any trees near by, and it you dig a hole 2 feet deep, what sort of ground is in the bottom of the hole?

 

[Inspector]

Our OP is trying to avoid hiring a pump, which is fair enough, because they cost a fortune. It also requires two large vehicles (the concrete mixer and the pump lorry), and with our confined streets and small plots that can be a real headache.

An idea of the site layout would be handy.

I understand not wanting to spend the money but with the OP talking about taking apart walls (brick, stone or block I presume) I thought it offset the cost and work of putting the walls back up, along with getting done quicker.

By concrete mixer do you mean the ready mix trucks that come from the cement plant or do you guys mix the ingredients on site?

Thanks for indulging my curiosity.
Pete

 

[Blackswanwood]

Our OP is trying to avoid hiring a pump, which is fair enough, because they cost a fortune. It also requires two large vehicles (the concrete mixer and the pump lorry), and with our confined streets and small plots that can be a real headache.

An idea of the site layout would be handy.

I understand not wanting to spend the money but with the OP talking about taking apart walls (brick, stone or block I presume) I thought it offset the cost and work of putting the walls back up, along with getting done quicker.

By concrete mixer do you mean the ready mix trucks that come from the cement plant or do you guys mix the ingredients on site?

Thanks for indulging my curiosity.
Pete

It’s ready mixed Pete

 

[Lons]

A team of 3 of us have mixed and laid those sort of quantities in a day on several occasions but it is hard work and we were experienced.
Another couple of options maybe?

1). Do you have enough space at the front of the house for readymix to be dumped so all you have to do is barrow and lay, assuming you have access from the front. You'll need at least 2 helpers, plus the wife to keep the tea coming. You also would need to have a large piece of sacrificial DPM to drop the concrete on to and would need to make some temporary retaining structure to hold it. Again something we did numerous times.

2). Again assuming you have access and it is a more expensive way to buy per cube but if you order from a company who mixes at the site they arrive with several burly lads who mix and barrow exactly the quantity you need outside the front dropped into the hole. You do need to count the barrows as it's been known their maths aren't always accurate. :roll:

 

[MikeG.]

.....By concrete mixer do you mean the ready mix trucks that come from the cement plant.....

Yes.

 

[Sheptonphil]

....... 3.7 m3 if my calculations are somewhere near.......

I see you're allowing for 125mm thick concrete. With your slab size that's your bare minimum. Ideally it would be at least 25mm thicker. Are there any trees near by, and it you dig a hole 2 feet deep, what sort of ground is in the bottom of the hole? An idea of the site layout would be handy.

Sorry, I appreciate without a plan it’s hard to offer help. Have added one here.

At approx 150mm we are on bedrock, I’ve just put nine fence posts in, after the first 150-180mm it was done with a breaker drill.

No trees near to worry about. On the site plan, south of the house is access for a hyab or mixer lorry to deliver over the ‘rendered wall to south’ in line with the green.

Removing spoil is more involved, access would be across the lovely (at present) lawn to get to the gate in front garage (pointy bit), as would getting a digger in.

The lane to garage has a dog leg, so a skip vehicle would have to be quite small to get up lane in reverse.

At 150mm is that circa 4.3m3?

I shan’t mention digger to SWMBO at the moment, we’ve only been here three weeks and she really likes the lawn. :?

 

[Sheptonphil]

A team of 3 of us have mixed and laid those sort of quantities in a day on several occasions but it is hard work and we were experienced.
Another couple of options maybe?

1). Do you have enough space at the front of the house for readymix to be dumped so all you have to do is barrow and lay, assuming you have access from the front. You'll need at least 2 helpers, plus the wife to keep the tea coming. You also would need to have a large piece of sacrificial DPM to drop the concrete on to and would need to make some temporary retaining structure to hold it. Again something we did numerous times.

2). Again assuming you have access and it is a more expensive way to buy per cube but if you order from a company who mixes at the site they arrive with several burly lads who mix and barrow exactly the quantity you need outside the front dropped into the hole. You do need to count the barrows as it's been known their maths aren't always accurate. :roll:

Hmm, I’ve added a site plan now, but no, there is no access to the site from front except over the wall. It’s a verrrry long walk (and three steps, then around house) to barrow it.

Thanks for the thought though.

Phil