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Hip to gable loft conversion
Posted by Isabella Evans on February 5, 2026 at 9:40 pmIs there any one on here that understands planning rules properly, I’ve been doing lofts for nearly 23 years now and we’ve come across a massive issue from the council, they are saying because the house has a double story side extension which is set back 800mm from the main house the council has said the customer can’t have a hip to gable because they are coming past the principal elevation on the front part of the extension which I have never heard of this rule being applied it’s always been you cat come past the original house elevation??
Donald Rogers replied 4 weeks, 1 day ago 8 Members · 11 Replies -
11 Replies
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It’s not a house on a corner is it? Where they might be arguing the PE is on the ‘side’ of the house? Plans or photos might help.
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i think there can only be one principle elevation. Corner properties used to have this problem years ago with old GPDO. I think more likely the problem here is the combined volume of the roof over the side extension added to the volume of dormer new hip to gable alterations being over 50 cubic metres ?
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no they arnt trying to go over the extension, they just want to bring the gable to the existing house edge.
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Done this to a property in Bromley. Took the flat roof off the double storey extension and went right out with a gable . 4 beds 2 baths in the loft . It was huge
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We done one the same and stepped the roof down on the lesser span and had a gable on the end.
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it’s the front hipped roof there saying we can’t change to a gable, which mean you can’t take the dormer across
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I believe the new principle elevation is now at the 800mm step back of the extension. This means you can’t bring the dormer to full planning as it will exceed it by 800mm if you drop it on the inner leaf of the existing house.
Your architect should be able to redesign the loft so it lands on the extension inner leaf but you might have trouble with the foundations of the newer extension not being deep enough.
It sounds extremely problematic but I would suggest going down the preplanning route before applying again.
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it’s the front where it steps in
Dormer is at the back, also how does the new extension take the new principle elevation? Surely it’s the furthest part of the building on the house.
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Sorry I should have said you can’t use permitted development you’ll have to go full planning.
Unfortunately it’s very technical wording but put very simply the new extension is the new principle. That 800mm faces the highway and everything will be decided from that, so you’ll have to do a preplanning application to see how much they would allow and then submit a full planning application.
It’s tough from the council but if you’ve been rejected (like I have several times now) look at the bottom of the paper work and they should have given you a number to call and I’ve found that to be very helpful to understand why you’ve been refused.
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Hopefully this can help. The PD to do a hip to gable only applies to the original house, not the side extension, so you should be able to hip2gable the orginal roof, but no more. There is no PD above the side extension.
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Get dorma on the side instead mate More chance of getting it past off from the council it will give you’re the head room what you’re need mate
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