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Building Homes or Extensions/2nd floor extension and roof modification


QUESTION: My house was built in 2001/2, it is part of a block of separate 6 houses (not flats), a tunnel runs through the block, to parking in the rear. The block itself is approximately square Pyramid Hip, made up of 4 triangular sections of roof sloping down from a single central point. 4 "corner" houses, in a standard ground & 1st floor construction with gardens/hard stand sit on each corner but they do not adjoin each other. Instead they each adjoin with various parts of 2 other "middle" houses which each have a ground, 1st & 2nd floor design. Essentially a thin slice for each of these houses exists between 2 corner houses on each side of the tunnel to provide an entrance & staircase up, then over the tunnel they each have their 1st (lounge/kitchen) & 2nd (bedroom) floor rooms, their bathrooms are on the 1st floor over the thin slice below. All houses have their front door out into the tunnel. My house is a "middle" house with the 2nd floor bedroom in part of one of the sloping roof "triangles".

I would like to:-

1. Take the 2nd floor bedroom to the wall, instead of a sloping roof/wall end we have at the moment, modifying a slice of the roof "triangle" using a gabled roof construction from the Apex in the center of the roof. Of course the current roof will need to have this section cut out and beams modified & walls extended up to take the new roof.

2. Make another 2nd floor bedroom over the bathroom, in a similar fashion to 1., where there is only a landing and roof now.

To me it looks do-able, we may have to have lightweight tiles for the new gabled roofs (to lighten load).

What do you think, and should we do it one extension at a time, and how long would a reputable builder take to complete each phase (in the summertime)? Could we still live in it? (only one small groundfloor bedroom).

ANSWER: You would need to give a lot more information about the structure of the buildings before I could give any advice on this. I would recommend you get somebody to come out and take a look at it, rather than ask online, as there are too many variables to consider. If the roof is trussed, and I would expect it to be given the age of the property, then altering it is not gong to be a case of just cutting and adjusting the timbers. Also these changes will probably require planning permission, and possibly even consent from your neighbours in the block. If I were you I would contact a local architect or surveyor.

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QUESTION: Of course the trussed roof will need a builders fix but there are ample builders out there who say they can do that. Re-bracing and hanging the remaining re-braced roof to the new walls, either side, I suppose.

Not sure why you say I will need planning permission though.

Both loft conversion ( ) and extension regs ( ) appear to be satisfied provided the side is obscure-glazed, as both are hip to gable roof modifications. Neither would extend outside of the current house walls and I am not in a protected zone.

Can you explain why you say that it required planning permission, please.

What consent would be required from the neighbours? and for what?

Hi, sorry for the delay. Permitted development guidelines are very useful for people who live in standard homes. With more complicated building designs,it is not straightforward.

Changing a hipped roof will have a drastic affect on the appearance of the building, which is partially owned by your neighbour, giving them a legitimate reason to object to the roof alterations.

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Martin Owen


Anything relating to the design and construction of extensions and loft conversions.


I currently work as an Architectural Technologist for, where I design extensions and advise on legal implications.

Degree in Architectural Design and Technology

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