Is building regulations advice correct? Other options..?

[Rubyblueshoes]

We would like to add a small extension to the back of our house to extend an existing extension (for a utility area). The current extension is about 1.3m deep (front to back) by 1.5m wide and the new extension would be about the same again. The total length will be less that 3m so we don't require planning. The new extension would sit on a patio that is already in place behind the house, which is 150mm of concrete on a bed of about 500mm of hardcore below ground.

A friend of a friend of ours works in planning for the local council (Croydon) so we asked him to come by and let us know our options so we can get the whole thing signed off as smoothly as possible he said we need two 1000mm deep foundations behind the existing patio which are tied into the existing structure with concrete lintels then we have two options:

1. Build a wood frame extension rendered externally. This'll cost us about £500 to get signed off.

2. Put a glass roof on it and an external glass door and call it a conservatory. We'd also need to have doors between the existing extension and the new conservatory but this doesn't require sign off.

What does everyone think? Does this sound about right? 1m deep foundations and concrete lintels sounds quite excessive for a 1.3m x 1.5m wood framed structure to us. The conservatory idea is ok, but we didn't really want internal doors.

 

[FresnoBob]

Conservatories separated from the main house via an external grade door are exempt from building regulations, once you take that door away the structure becomes subject to building regulations (and the fees and inspections).

Not sure about that advice about a glass roof though, I thought the percentage glass/glass roof had been scrapped in the latest building regulation definition of a 'conservatory'? Somebody more knowledgeable will confirm or correct me no doubt.

 

[freddiemercurystwin]

Of course you need foundations even for a timber framed extension. You need to retain the door unless its a proper extension. If your friend from the planning department is a typical planning department bod I wouldn't trust a word he says when it comes to Building Regs. Or are you getting Building Control and Planning confused? They are totally separate.

If you're really interested for the definitive definition of a conservatory see this thread here: //www.diynot.com/forums/viewtopic.php?t=278544&start=0

But to save having to read all that blurb in that thread read the following, referring to the document in the link:

http://www.planningportal.gov.uk/uploads/br/BR_PDF_ADL1B_2010.pdf

If the conservatory complies with 3.15 (and 3.16) it will be exempt from the regs no matter how much or little of its roof or walls are glazed. Building such a conservatory is not notifiable.

If it does not comply with 3.15 it must comply with 4.8, there is no limit on how much or little of its roof or walls are glazed. Whilst it must comply with the regulations stipulated within 4.8 building such a conservatory is not notifiable.

If it does not comply with the above it is not exempt from Building Regulations Approval and to become a lawful development Building Regulations Approval from the LA or an Approved Inspector is required.

 

[paulf1976]

The LABC advise something slightly different but more or less along those lines. Most LAs will follow this guidance so this would be a good starting point.

You would need to get clarification from the LA if they think your 'conservatory' is deemed that in their interpretation otherwise you will struggle to prove it when the time comes to sell!

Most LAs provide an Exemption Certificate for a small fee for proposed and existing buildings.

[url]http://www.labc.uk.com/home-owner-guides[/url]

 

[freddiemercurystwin]

You would need to get clarification from the LA if they think your 'conservatory' is deemed that in their interpretation otherwise you will struggle to prove it when the time comes to sell!

A development such as this is either a conservatory or it is not. If the OP removes the door he'll need that certificate of Regs Approval from BC for an extension.

 

[Rubyblueshoes]

If your friend from the planning department is a typical planning department bod I wouldn't trust a word he says when it comes to Building Regs.

Now you come to mention it I'm not sure if he's from building control or planning, either way, I wouldn't exactly describe him as a friend Anyhow thanks for the link freddymercurystwin that clarifies the conservatory issue perfectly.

The only other issue that would be great to get some thoughts on, is the foundation.

I was discussing it with a friend who has just completed a major extension on his house, two story, blockwork, tied into the existing roof and he was told initially to go 1m deep on the foundations, though they did up it to 1.5 after discussions. Makes our recommendation of 1m deep for a single story wood frame lean-to seem rather excessive.

So really what this boils down to is: If we go the conservatory route, and building control is no longer an issue, what would anyone here recommend as suitable foundation for 2.0x1.4m lean-to? Any chance the existing 150mm concrete slab is sufficient?

 

[Rubyblueshoes]

Just realised this secondary question is probably a more relevant question for the building section so I'm going to repost this over there.

New post with more accurate measurements: here

 

[freddiemercurystwin]

You would need to get clarification from the LA if they think your 'conservatory' is deemed that in their interpretation otherwise you will struggle to prove it when the time comes to sell!

The definition of a conservatory has been explained in this very thread.