Foundations for conservatory with dwarf wall and tiled roof

piper64 · 5 Jan 2021

Does a conservatory built with dwarf walls and a tiled roof need to be treated as an extension? As I understand it, an extension needs foundations deep enough to carry a two storey build, but a conservatory doesnt. Due to access, any digging would have to be manual, hence my reason for asking.
Would it need permission as the information I've found suggests not, but I can see posts on this forum where permission was required?
A small 3m x3m conservatory is existing, but is the standard 'all glass with plastic roof' type and I was thinking of replacing it with a larger, more useable one.
Thanks

^woody^ · 5 Jan 2021

piper64 said:
As I understand it, an extension needs foundations deep enough to carry a two storey build

No. An extension needs foundations deep enough to stop it sinking or bobbing about. Same criteria for a conservatory.

A conservatory is exempt from building regulations as long as you follow the exemption criteria - basically keep below a certain floor area, keep the door to the house, heating that is isolated/isolatable from the main system.

Otherwise it's not a conservatory, but an extension and needs permission as such.

piper64 · 5 Jan 2021

Cheers, good to know.
I have read that a conservatory or an extension doesnt need permission so long as it's not bigger than a certain size and such.
When does a conservatory become an extension apart from the points you mention?
I would intend to have a tiled roof, plastered ceiling, couple of skylights....like a sunroom or large porch.

frutbunn · 6 Jan 2021

piper64 said:
I would intend to have a tiled roof, plastered ceiling, couple of skylights....like a sunroom or large porch.

Its not exempt from B regs in that case.

^woody^ said:
Same criteria for a conservatory.

In reality rarely the case, I've seen one built on tarmac and quite a few just on yard/patio slabs, over made up ground etc..

^woody^ · 6 Jan 2021

Building Regs Classification of a Conservatory | DIYnot Forums

piper64 · 6 Jan 2021

Ok, so no tiled roof then, but the main issue for me was the foundations side of things really, so as it technically is not deemed to be a conservatory ( but it will used as one) , does that affect the required depth of the foundations?

frutbunn · 6 Jan 2021

piper64 said:
Ok, so no tiled roof then, but the main issue for me was the foundations side of things really, so as it technically is not deemed to be a conservatory ( but it will used as one) , does that affect the required depth of the foundations?

If it needs B Regs then follow the very general advice in one of my previous replies, in any case it will need to be inspected by a BCO.

^woody^ · 6 Jan 2021

DCLG guidance 2013
"It must be at ground level;
• It must not exceed 30 m2 in floor area;
• The glazing must comply with Parts K4, K 5.1, K 5.2, K 5.3 and K 5.4 of Schedule 1;
• The thermal separation between the building and the conservatory or porch must be maintained; and
• The building’s heating system must not be extended into the conservatory or porch."

Those are the only criteria. Is "no tiled roof" mentioned?

I think you are confused about the foundation and building regulations. It is the ground that demines the foundation depth not building regulations. Just because building regulations don't apply, does not mean you can skimp on the foundations - well you can if you like, but then live with the consequences.

The requirement for any foundation, building regulations or not, extension, conservatory, BBQ whatever, is that foundations are "suitable". And what is suitable for my conservatory might not be suitable for yours.

piper64 · 6 Jan 2021

Hi chaps
I'm not confused, however I now know that a tiled roof means its not classed as a conservatory. That's one issue.
That brings me to the next. All my reading regarding a conservatory suggests the foundations should be 'suutable' as there is no minimum. I would not be building on top of tarmac or slabs of course.
Clearly I would make them as deep as I could, but as I mentioned, it would all have to be done manually.
If it is not going to be classed as a conservatory now, do the foundations come under different rules regarding depth ( in addition to any ground conditions) is what I was wondering?

piper64 · 6 Jan 2021

@woody No tiled roof is kind of suggested under the "The extension has a completely transparent or translucent roof." criteria.

Read more: https://www.diynot.com/diy/threads/...ation-of-a-conservatory.278544/#ixzz6im5pUoZG

frutbunn · 6 Jan 2021

piper64 said:
@woody No tiled roof is kind of suggested under the "The extension has a completely transparent or translucent roof." criteria.

Read more: https://www.diynot.com/diy/threads/...ation-of-a-conservatory.278544/#ixzz6im5pUoZG

As far as I am aware all local authorities are following the interpretation of a conservatory (clear/translucent roof) in the linked doc., certainly all of the authorities from Northumberland to North Yorks follow this interpretation, as has been the case since the exemption for conservatories was introduced in 1982, but Woody as always knows better.
https://www.labc.co.uk/sites/default/files/labc_4893_techg_conservatories.pdf

freddiemercurystwin · 6 Jan 2021

Guidance isn't lawful though is it?

^woody^ · 6 Jan 2021

frutbunn said:
but Woody as always knows better

I knew you would come to your senses one day.

^woody^ · 6 Jan 2021

frutbunn said:
https://www.labc.co.uk/sites/default/files/labc_4893_techg_conservatories.pdf

Are you sure that that document is the latest?

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Foundations for conservatory with dwarf wall and tiled roof

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