Cost of knocking down a supporting wall

Relbs

Hi, 
I had a someone around to draw up plans for some internal building work in my house. They told me it would be very expensive to knock down an internal wall (highlighted in yellow) because it was originally an outside wall, therefore it is a supporting wall. Instead they advised extending a different room to get extra space (green drawing on floor plan).
Is it an absolute "no way" to knocking down a supporting wall, or just more complicated (& a bit more costly) than knocking through a non-supporting wall? 
I have attached the floor plan in case that helps. 
Thank you

MikeJXE

You're bedt to get a structural engineer to tell you 

Emmia

You'll need to ensure the building above is supported, which would mean joists would need to be added - adding joists makes it more difficult to have a clean single room feeling.

And, you'll need a structural engineer.

Doozergirl

Anything can be done, it's just a matter of how much money you are prepared to throw at it. 

We can't see the whole floorplan, which is important.  Without doubt, from what I can see,  you need a structural engineer to start with.  It doesn't look hugely complicated though.  

ThisIsWeird

Of course it can be done, Relbs.

But, if this builder is suggesting additional room as being a similar-cost option, I'd be tempted. You'd be opening the dining room into the new room via the existing window? Easy. That could become a lovely sunny room, even also opened to the kitchen if you liked, and you'd still have a separate reception room in that sitting room.

That's a skylantern in the sitting room? Like it? You could have another in the green extension.

Yes, you'd ultimately need an SE to determine how to support the opening if going with your original plan, but perhaps worth getting another builder in to give ballpark figures too - compare the two options?

GDB2222

In your op, you talk about the work being a bit more expensive. There’s also the possibility that it’s a lot more expensive! 

GrubbyGirl_2

Perfectly doable but you will need a structural engineer.  I had 2 walls removed shown in yellow and the red shows where the original external walls were, so you can see I basically removed the original corner of the house.  The engineer did the calculations and they were pretty hefty steels that had to go in.  As for cost I can't tell you the labour costs as they were all included in the overall house renovation cost but the steels alone were in excess of £2,500 and that was 3 years ago

GDB2222

https://forum.buildhub.org.uk/topic/9294-lifting-heavy-rsj/

silvercar

Just had similar done. There are always options and the cost depends on the balance you want to make between appearance and cost. To completely remove our wall was silly money, to have a support pillar in the middle was cheapest, but that was not  the look we wanted. In the end we went for "nibs", a bit of wall left on either end. 80% masked on one side by having units on both sides of the nib; not so discreet, but bearable on the other with a unit on one side of the nib and not on the other. Still talking a 5 figure sum.

Section62

Relbs said:

Is it an absolute "no way" to knocking down a supporting wall, or just more complicated (& a bit more costly) than knocking through a non-supporting wall? 

I have attached the floor plan in case that helps. 

The floor plan suggests there have been various alterations done in the past - this can complicate structural alterations, and for 'complicate' read 'make expensive'.

The feasibility/cost of the proposal will depend to a great degree on whether the affected parts of the property are single storey or double (or more), and the type of roof.  If (as the floorplan hints at) parts of the building are single storey with a flat roof then the engineering may be easier than otherwise.

As Doozergirl suggests, most things are doable, given enough budget and will.

However, if you have the opportunity to extend, and have the benefit of only needing two new walls, then (subject to planning issues) the option that makes more sense economically may well be adding floor space as with this you'll be getting more room, not just a modified layout.  That said, if the property has already been extended (and particularly with a flat roof) then adding further extensions may not be as straightforward as it may seem from just a ground floor plan.  Full floor plans and external photos are really needed to get meaningful answers to the question.

daivid

@Relbs Extending as shown will have light implications on the kitchen and dining rooms, unless you are going to knock through (in which case issues of supports and external walls come up again). It could be that an extension is more 'cost effective' in terms of value added vs cost of project but unless the putting in of a steel is an extremely complex case that will cost far less. 

Did you ask the people who came round for an idea of how much knocking through would cost? The cynic in me wonders if they were trying to drum up a more lucrative job in the extension. As everyone else has said, if you want a reasonable estimate of cost you need a SE to visit and clarify the complexity (or lack of) for what your house needs. A SE visit and plans drawn up would cost a few hundred pounds but will be money well spent if the knock through is what you really want.