More builders advice please?

This is the rear of my new house (not the exact house, but exactly the same house style from the same builder)



This is the current floor plan for the ground floor




See the little extension at the back that makes up half the kitchen?
Would it be possible to extend the same roof all the way along the back of the house, to achieve this?




There must be an RSJ over the kitchen at the moment? Would I be able to put another one in over the rest of the kitchen, welded to the existing RSJ and supported on the kitchen/living room wall, and the outside living room wall? Or would I need to take the existing RSJ out and put a new one in the full width of the house from outside wall to outside wall?

Would this leave a beam in the ceiling or any protruding pillars required on the interior walls?

About how much do you reckon it would cost?

Thanks

Ask the builder for the structural engineer's calculations. You will need your own engineer to calculate the loadings on a new beam. A builder might be able to do it but they generally don't carry professional indemnity insurance, and besides the building inspector will ask to see the calcs.

Nice gaff!!!!

[MisterTommyH]

The beam thats in there already will be sitting on the corner between the utility and the kitchen.

The second plan doesn't have this wall anymore so you'll have to put a completely new beam in. The span is greater so the beam will need to be bigger (in capacity - it might be possible to get one of the same depth to work though). You'll also need another beam (possibly re-use the existing from over the kitchen) to sit over the lounge/diner to support the external wall and first floor above.

From eyeing it in this looks like it might sit just be over the double door you've got shown so you'll need a decent beam over that door rather than a simple lintel (unless you want to move the door so that it's not central in the panel).

Also both beams would be bearing onto a single leaf wall between the diner and the kitchen - you'll probably need a pier there to get a decent bearing for both (This assumes that the existing GF wall is masonry not stud).

Finally, by doing that you'll be changing the way the load goes into the foundations - do you know what the foundations are? In most cases this shouldn't be a problem, but if it's piled or if they're very skinny then it's something worth getting looked at.

[MisterTommyH]

Originally Posted by Ed

Ask the builder for the structural engineer's calculations. You will need your own engineer to calculate the loadings on a new beam. A builder might be able to do it but they generally don't carry professional indemnity insurance, and besides the building inspector will ask to see the calcs.

Nice gaff!!!!

Very unlikely to get the original calcs Ed. We don't provide copies on principle. For something like this you'd probably want someone to do it as a foreigner - A lot of companies would find it too small and charge the earth.

If you need calcs shout and I'll see what I can do for beer tokens. Don't carry PI though.

Tommys correct, you will need a new beam spanning the new area.

If the divide wall between the lounge and larger ktichen was reconstructed and widened, you could have both beams supported from this to the outer walls.

Ive done similar to this, the architect for that job specified a 10x6 beam which was ridiculously over size (and he told them they could have a flush ceiling but only had 6inch floor joists), i got new calcs done and used a 8x8 RSJ, which also supported a 6x4 perpendicular to it.

I dont think you'll need one as big tbh looking at it.

Id be amazed if foundations would be a problem but does depend on the ground in that area, ive been lucky in the areas i work in, its good clay.

For the cost id try and go another metre out, it wont cost that much more tbh.

Between me and you, i cost extensions at approx £800-£1000 per sq metre for the shells, beams, roof windows, french doors all add to this.

A different brick can add £500 to a extension so i have to be careful with quotes.

[skeetly]

That's way outside what Reg's will allow normally.
Modern houses like that are built within certain parameters that you can read about here:

http://www.planningportal.gov.uk/upl..._AD_A_2010.PDF

From about page 25 onwards should be helpful.

You can get round them by hiring a good engineer and using lots of money.

I did type out a big long reply with lot's of technical stuff but it was getting ridiculous and I had ended it with this picture:






Good luck.

Originally Posted by Tommy H

Very unlikely to get the original calcs Ed. We don't provide copies on principle. For something like this you'd probably want someone to do it as a foreigner - A lot of companies would find it too small and charge the earth.

If you need calcs shout and I'll see what I can do for beer tokens. Don't carry PI though.

My structual engineer charges me £80 per calc, he gives me a copy which i copy myself then give to the BCO, they then pass it on to their 'checking' dept who just enter info in their bit of software and say yep thats ok.

Problems start when architects think they are engineers.

[MisterTommyH]

Originally Posted by skeetly

That's way outside what Reg's will allow normally.
Modern houses like that are built within certain parameters that you can read about here:

Nae sayer!

It is above permitted extension (3.5m sq). So you'll need a planning approval, but unless it's tight against a side boundary I wouldn't think you'd have any problem getting it passed.

Originally Posted by specialone

My structual engineer charges me £80 per calc, he gives me a copy which i copy myself then give to the BCO, they then pass it on to their 'checking' dept who just enter info in their bit of software and say yep thats ok.

Problems start when architects think they are engineers.

I'll do you £50 and a .pdf copy ha ha.

On jobs this size that is what I'd do, but on a big estate with multiple copies of houses and probably 300 plots we would deal with BCO direct and the developer would never see the calcs.

Thanks v much for the reply Tommy!

Originally Posted by Tommy H

The beam thats in there already will be sitting on the corner between the utility and the kitchen.

The second plan doesn't have this wall anymore so you'll have to put a completely new beam in. The span is greater so the beam will need to be bigger (in capacity - it might be possible to get one of the same depth to work though). You'll also need another beam (possibly re-use the existing from over the kitchen) to sit over the lounge/diner to support the external wall and first floor above.

OK, understood. I never thought about taking the existing beam out and putting a new beam for the kitchen, and another for the lounge (but that's why I'm not a builder ).

I take it having to remove the existing kitchen beam adds a lot of cost? This is basically just to allow us dining space in the kitchen or lounge (or both), so we can use the 'dining room' for something else. We only use a dining room when we have guests, and unless there's 6 or more people we end up eating at the kitchen table, so it's a waste of a room. We do need occasionally to seat 6 or more people though, but we'd be happy to do that in the lounge or kitchen.

The other option of course to keep the existing wall (and reduce cost?) is this, and there's a lot to be said for a utility room when you have a dog with muddy paws.



Still it's a 5 bed house, so there's plenty other rooms that could be a playroom, so I wouldn't spend the earth to achieve it. If it were 20 grand or less I might do it, if it were 30 grand or more I definitely wouldn't

Originally Posted by Tommy H

From eyeing it in this looks like it might sit just be over the double door you've got shown so you'll need a decent beam over that door rather than a simple lintel (unless you want to move the door so that it's not central in the panel).

Also both beams would be bearing onto a single leaf wall between the diner and the kitchen - you'll probably need a pier there to get a decent bearing for both (This assumes that the existing GF wall is masonry not stud).

Would be happy to shift the door, no idea what the existing wall is. Haven't moved in yet so I can't bang on it to check! If it was a stud wall that would need a proper foundation dug and replaced with a masonry wall wouldn't it? I think that would create enough mess to knock the idea on the head.

Originally Posted by Tommy H

If you need calcs shout and I'll see what I can do for beer tokens. Don't carry PI though.

Cheers Tommy, it's a Taylor Wimpey house.

[MisterTommyH]

Is it a new estate or a few years old? Do you know what the estate is called (as in what Taylor Wimpey called it when it was sold rather than it's local name)?

Theres a chance that we would have done the fnds design.