External wall - Lintel/RSJ

[noz81]

Hi

Excuse my complete lack of building knowledge, i'm looking to make some changes to the downstairs layout of my 3 bed semi and found this forum so thought someone might be able to help...

We have a single story extension on the back of the house, this currently has the kitchen in it and a utility room. The wall between the dining room and the kitchen is obviosuly the original external wall of the house and holds the whole house up, it is a cavity wall. The gap between the dining room and kitchen is currently about 1.3 metres - no door, just an opening, we'd like to increase this to about 3.5 metres (The wall is roughly 5.5 metres wide in total) to try to get some light in and try to make more of a kitchen-diner as the dining room is currently really dark..

Does anyone have any advice about where to start here? Firstly, is it possible to make a gap this big in the external wall? Who do i need to speak to first? Builder/Structural Engineer/Building regs (Which i know nothing about) or would the builder take care of this? Also, if it is possible, roughly how much should i be looking to pay to get it done and how long would it take?

Any help/advise would be most appreciated...

Thanks

 

[hotrod]

Yes it's possible, it's pretty standard fayre for a general builder. You have a couple of options:-

1. Approach a Structural Engineer to specify the RSJ/UB for you and then give this to a builder(s) to quote.
2. Find a builder you're happy with and let them deal with the Structural Engineer and Building Control.

You're probably looking at approx £200-£300 for a Structural Engineer to do his bits and bobs.

 

[noz81]

Thanks for the info, i have another question... roughly what width of bricks would be needed at either side of the lintel to support it?

 

[hotrod]

For a span of that size you would require a minimum end-bearing of 150mm, with the steel sat on padstones. I think Woody's got some details in his album, if you ask him nicely he may oblige and put one up for you .

 

[noz81]

cool, pretty please Woody, please would you oblige?

 

[noz81]

Right, i've had a builder round, who was reccomended to me.

He advised that he'd need his Structural Engineer friend to come round and do some calcs for the steel which would cost me around £250 and the SE would sort out everything with my council building control - another £150. I asked him for a rough estimate of how much he thought the job would cost (I wanted an idea before i fork out the money for the SE) and he reckoned about £1300-£1400 for everything (Inc. SE and BC fees, the steel, labour - around 2-3 days, moving a couple of plug sockets and plastering/making good)

Can anyone advise if this sounds about right? I dont want to find the price will go up loads once the SE has been round and obviously dont want it done on the cheap - the biulder was very professional though, insisted on the SE and BC sign off on the steel before starting the work so dont think he'll be the type of cowboy to do it on the cheap but just wanted some opinions??

Ta

 

[hotrod]

Sounds very reasonable to me. Say £400 professional fees, £300 materials, that leaves him £700 for 2 days work (say 4 man days @ £175 inc vat). Plus it depends how much "making good" there will be, but it's not going to be a million miles away.