Extension/ House Buying Help

Structural engineer here, so my 2 pence:

It depends entirely on what's involved, it does sound high to me but there are a lot of unknowns at the moment. The main things that would bump it up are:

• Is the roof trussed, or are you having a vaulted ceiling inside? If it's trussed it will be sub-contracted out and all they need to do is check the drawings/calcs from the truss manufacturer - therefore trusses are cheaper.
• How old is your house? Older houses mean more pain from a structural point of view, the stability can be an issue when knocking through meaning you need a steel frame. Steel frames take time and money to calculate.
• Is the opening into the new extension going to have flush walls, or are you leaving in piers? Again, piers provide stability so a flush wall will mean an expensive steel frame and calcs.
• How many windows & doors are there? Lintels take (a little bit of) time to calculate, but if openings are wider they may need steel beams rather than lintels off the shelf - it's also worth noting that lintels are like gold dust at the moment and some builders are asking to design each lintel as a steel beam, which takes longer.
• How wide is the opening between new and existing? I think I saw 1.7m, if so that's nothing and I'll tell you for free that's probably a couple of UB 178x102x19 beams.
• If they're doing the foundations, will they be piled or trench fill? What soil do you have? I don't expect that's been investigated yet, but if you're in a notorious area that may have been factored in.
• Is the extension an awkward shape which means (for example) a corner of the building is being removed and needs supporting/reinforcing? If so, then that will add hundreds to your bill. If it's just bolted onto the back then it should be cheap.

It's an odd industry at the moment, builders are struggling to find supples and as such material prices are skyrocketing, but at the same time everybody and their cat wants something built. We're actually rejecting all domestic work at the moment because our workload is too high, so I guess those still taking on domestic may be exploiting the situation if they're that way inclined. Are you pushing for a quick turnaround? This may also cause them to chuck on a few hundred extra.

I can't take anything else on at the moment, plus presumably you're outside of our catchment area, but if you want to PM me details/drawings I can send you a representative quote.

 

It’s understandable that people will want to alter houses and sometimes that will be quite considerable. Having lived next door to a ‘project’ I can tell you that it can be an effing nightmare for neighbours.

If anyone’s project for their terrace or semi-detached is essentially effing off for a year while your house is gutted and the concrete floors broken up, then I suggest you give up on being friends with your neighbours. It’s a thoroughly antisocial thing to do and however pleasant your builders seem they will make a ****ton of disruption for others even if it’s just nine months to a year of a flipping site radio blaring.

 

Understandable. I get on very well with my neighbours on both sides and they haven't voiced any objections/concerns to me. Behind my house is the A405 so I don't have too many people to inconvenience.

For me this is the first and hopefully last time I do something of this nature.

 

Congratulations!

 

Eight years ago, we had a structural engineer do some work regarding underpinning following a broken drain washing away the sub soil around a foundation;. That cost £600 +VAT. Then we had to have him look at the roof, and options for a loft extension. The build loading calculations made it impractical without more steels than normal, because of the arrangement of internal walls. That was another £600.

We also used an architect, and he suggested the SE. It’s just my opinion, but unless you are an informed buyer, you need to trust your architects opinions on SE and builders they work with. One reason to get to talk to as many of their past clients as possible.