Extending by opening gable end with fireplace

BoardsMember

We have a semi-d circa 1920's house. We want to extend to the side, the gable end. The house has two receptions rooms, 10ft ceilings, each 4m * 4m, so nice size square rooms. We want to access the extension via on of the reception rooms.

To make the extension part of the existing house as much as possible, we want to knock some/all the wall of one of the rooms. Ideally it would be all of the wall, to near ceiling height. This would stop the existing room becoming just a way to access the extension.

The added complication is that there is a fireplace with large chimney breast, about 2 metres wide, in the middle of the wall. There is also a redundant fireplace in the bedroom upstairs.

The ideal scenario would be to have the wall completely opened up. We could then put in some sort of two sided stove at floor level but above it only the chimney of the stove. I don't mind if the steel is not flush with the ceiling of the existing room. (The extension will likely be one or two steps down from the existing room). This would leave us with great space, the extension would contribute to a nice large open plan L-shaped room that would have kitchen/dining/family room spaces. The extension itself will be circa 9metres long/5 metres wide.

A compromise would to slim down the existing chimney breast as much as possible, and open up either side of what is left, so there would be two "entrances" into the extension on either side of what remains of the chimney breast.

Anyone come across this type of thing? Anyone got any idea of the cost of this type of work? Obviously steels/engineering are involved. I just want to see if anyone has done anything like it, or would have any suggestions/recommendations for how to approach it, and perhaps get a feel for what costs might apply to the approaches available.

We're very much at a pre-planning stage. The intention is to get QS for initial budget estimate, and this would be a critical part of their input. But we're not in a position to kick the project off yet, so just mulling over the options. Thanks

BryanF

BoardsMember wrote: »

1. Anyone come across this type of thing?
2. Anyone got any idea of the cost of this type of work? Obviously steels/engineering are involved.
3. I just want to see if anyone has done anything like it, or would have any suggestions/recommendations for how to approach it, The intention is to get QS for initial budget estimate, and this would be a critical part of their input.

1. yes, altering/ removing chinmeys etc seems like a big job, but i'd presume you'd be moving out while extending the house, so a contractor with eng support will have no issue in carrying out this work.
2. 9x5=45msq + internal structural alterations, in what county, main contractor, 1920's house, somewhere between 70 - 140k (id include a min 20% contingency in this)
3. yes, you answer your own question - employ an architect and qs

BoardsMember

Thanks for the response BryanF

BryanF wrote: »

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i'd presume you'd be moving out while extending the house

Yes, but ideally the works would start on the actual extension while we stayed living there, and we'd only move out when the work to break the rooms in started. Obviously, if it was more costly to do it this way than move out for the duration of the build we'd have to look at the figures.

BryanF wrote: »

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9x5=45msq + internal structural alterations, in what county, main contractor, 1920's house, somewhere between 70 - 140k (id include a min 20% contingency in this)

Thanks for this. Was really only trying to get a handle on what the cost implications might be for slimming down the chimney & having two entrances versus taking the whole wall out.

BryanF

BoardsMember wrote: »

Thanks for the response BryanF



Yes, but ideally the works would start on the actual extension while we stayed living there, and we'd only move out when the work to break the rooms in started. Obviously, if it was more costly to do it this way than move out for the duration of the build we'd have to look at the figures.



Thanks for this. Was really only trying to get a handle on what the cost implications might be for slimming down the chimney & having two entrances versus taking the whole wall out.

you need to put the cost of this context of what overall works your doing. my reading of your questions are that you're tied-up on this aspect, if i may id suggest this work could be in the region of 2500k so possibly 1/2msq of the cost of the extension. you could drop more on extra lighting at the end of the build than on this. pick your arch carefully, dont scrimp on service and take on the qs. they'll help you through this project. best of luck

(edit: do note your existing homes retro-fit scope will in most instants use up far more money than you expect)

BoardsMember

Thanks for this input. The overall project will indeed ensure this pales in comparison, we need to re-wire, put a second floor onto the extension we'll be building, and do lots of other bits and pieces. So your ball-park answer has put this into perspective - we should be aiming to knock the whole wall if at all possible.

When we have finance in place the QS is definitely where I will start, then look for the architect.

I think your suggestion re contingency of 20% is wise, I am not a risk taker by nature and, though this type of project really excites me, the financial cost of it terrifies me!