PD - Substantially Non-Combustible Materials.

[Ron_UK]

Hi All

I'd really appreciate some help regarding permitted development. here's a brief explanation :

I'm looking to build a very large Leisure Shed in our narrow garden and it's going to be 0.6 Metres from the boundary's on the left & right sides. My worry is the term substantially non-combustible materials.

Planned EXTERNAL Specs :

• Maximum height total = 2.5 Metres.
• Taking up 25% of the total Curtilage and 20 Metres from the house.
• 0.6 Metres from boundary's on both Left & Right sides.
• Concrete Slab.
• Celcon Block construction with silicone render.
• Standard Tile or Formed Metal Roof on Plywood Boards / Wooden Joists.
• UPVC Windows / Door.

Planned INTERNAL Specs :

• Maximum internal floor area of 29 Square Metres.
• Raised wood floor using 6x2 Joists and Plywood sheets.
• Fully Insulated using 50mm Celtex to Ceiling, Walls & Floor.
• Plasterboard over the Celtex on Walls & Ceiling.
• Fully Underlaid & Carpeted over the whole floor area.
• Internal Electrics (To be done by myself but professionally approved).

Can anyone see any worrying issues?

I do plan to get a Lawful Development Certificate but wish to solve any issues first as to better my chances.

Many thanks
Ron_UK

 

[noseall]

My worry is the term substantially non-combustible materials.

Mine too, oh Lordy.....
https://www.diynot.com/diy/threads/timber-frame-garage.403693/page-8
You may find bits of it interesting.

 

[Ron_UK]

Thanks noseall, that thread turned into an argument, lol!!

Think i'll just do my plans and specs, send them in and keep my fingers crossed, they can only say yes or no.

If anyone else can advise it would be appreciated.
Thanks
Ron

 

[motorbiking]

how big? Under 15m2 and its fine

 

[^woody^]

Permitted development (planning) has not got anything to do with combustible materials (building regulations)

 

[John D v2.0]

Celcon block and render is fine, as long as no large windows or doors in the side elevations facing the boundary. Less than 1m2 should be OK. Roof should be fine, it's basically flat anyway.
If you had timber frame you'd have to triple plasterboard the inside and the equivalent on the outside!

 

[oldbutnotdead]

Think you're OK on the non-combustible bit- the walls are the main concern (re spread of fire to the neighbours' house/garden). Be prepared for some flak regarding the wiring- if everything in there was going to be surface wired then you could design and install it yourself then get a Part P spark to verify the install, test the cabling and make final connections. You've got the small issue of supply to the building (how big a cable do you need, is it going underground, where will you connect to the house supply, what will you put on the shed end..... you really need to be consulting your electrician at the design stage for cable sizes etc and then work to his/her instructions when you put the cabling in.

Another thought regarding the floor- why not put the insulation under the slab and skip the whole joists/plywood sketch? There's a fair old saving to be had there (ply isn't cheap, nor are 6 x 2 timbers). Of course you'd need to dig strip foundations for the walls.

And a final couple for you to ponder. Where's the runoff from the guttering going to go? And have you thought about the convenience of putting some plumbing in

 

[Ron_UK]

Hi Motorbiking & John D, and everyone else.

You already helped me with a future project regarding my small shed electrics but this BIG venture is one in the planning.
Hoping to build a large Leisure Shed, a place to have some fun

I see what you mean by the plumbing oldbutnotdead, there's going to be a lot of water running off that roof!
It's possible to run a long pipe so it flows into the house drainage as a water butt would fill in minutes!

Not sure about putting insulation under the slab, it's an idea i've always disliked.
By having the raised floor means i can get some air flow under the shed to hopefully eliminate damp.

Regarding the electrics, this you have already helped me with regarding my smaller shed BUT i will call in a sparky
before doing anything on that side, best to be sure and your advice on this has already been brilliant.

John D, i'm pleased i made a good choice with the Celcons and Roof types, they seemed the best choice.
Also having the internal walls & ceiling plasterboarded adds the extra protection.

Regarding this project :

I plan to do the design, foundation, bricklaying, woodwork, roofing and electrics myself, jack of all trades me!
Will create a dedicate thread showing progress pictures and costings through the stages so people can following what i do wrong, lol!

Thanks again for everyone's help.
Ron

 

[tony1851]

Most councils would regard your roof and walls as 'substantially non-combustible', though possibly not the floor - could it be done as a slab?

 

[Ron_UK]

Hi Tony

Well i wanted the floor raised because i wanted to get some air flow under the flooring to reduce the risk of damp.
The floor will also be carpeted so plan was Celotex between the joists then Plywood then underlay then carpet.

I will be applying for a Permitted Development Certificate but does that cover the building regs as well?

Thanks
Ron

 

[tony1851]

A Certificate of Lawfulness does NOT cover Buildings Regs - completely separate issues.

 

[Ron_UK]

Hi Tony

Thought so, thanks for confirming.
I may start a new thread on the Lawfulness subject as it may help others.

Thanks
Ron