Extension cost cutting

[Bythebeach]

A plea to pick the brains of those who’ve done this before. We have plans drawn up for a 4m by 7m extension to make a kitchen-diner and need to minimise cost. The architect has designed in high (2.3 vs 2.1m) bifolds and windows and a roof lantern. I love light airy rooms but in all honesty need to cut costs so am planning to ditch the roof lantern. Presumably it would also be cheaper to have French doors with side panes instead of bifolds? And would it be cheaper to stick to some sort of standard sizing for doors and windows? Any recommendations for guidelines or suppliers? Any other easy cost savings before we start or as we proceed? I can’t project manage it myself as not enough time or knowledge but want to know what I can look out for in both final design and with our builder to ease the finances. Thanks!!

Have you had to apply for planning permission? If you make changes you might need to re-apply for a variation (not sure that's the correct terminology). Also, cost any proposed changes out fully as, in the scheme of things, it might not save you as much as you think.

I have done a kitchen extension, and you have to remember if you compromise on something now you may regret it later and it may take the shine off how you feel about the extension.

So, if you want to keep the roof lantern then keep it. Is the alternative velux? How much would that realistically save you?

Bi-fold doors, buy ready made rather than bespoke, just get the builder to make the aperture the size of the doors.

I have a bay window with French doors in my lounge which overlooks the back garden. The french doors have a stay open device to keep them somewhat locked in place, but they do not intrude on the patio area. If you were looking at bi-folds surely they stack back to one side, French doors may impose on your outdoor space.

The main thing I did for cost cutting was on things like lighting, sink, tap, dishwasher, fridge freezer etc so I found ones I liked then searched to find the best deal on it. All online although I did visit Currys to feel the quality of the brands of dishwasher and fridge freezer.

Your builder should be full of knowledge of where to buy stuff. My builder had been in the trade for 20 years and had a wealth of supplier information etc.

If you need to cut costs then maybe get the structural things in place but wait for things like flooring, new furniture etc. Like I said, you may kick yourself. I refused to compromise on my £850 induction hob. It is a joy to use it almost daily. The compromise was the Beko dishwasher instead of a Miele one but the dishes are still clean

Thanks for the comments. We have pre-planning approval thingy but not permission as yet but unlikely to be an issue given neighbours in agreement and similar extensions.
Cherulewis - thanks. I’m trying to think about what I really want from the extension so a roof lantern wasn’t in my wish list but liked the idea of it initially when architect suggested it but if it’s £3k I can save, I need to save it! Good point on talking to the builder about suppliers. I will do so. I am anxious as we had permission for a different design which really opened up the back of the house but the structural design and quotes we got in for that build were astronomical because of the complicated and massive steels. So we had to go back to the drawing board!

Had the architect suggest bi-fold doors due to space constraints? Is there even enough room to put in ordinary doors?

I don’t think it was space constraint BikeSki....

My own extension was a simple one. I had done a lot of research, reading renovation/home building magazine, been to shows etc and drew my own plans for both the garage conversion and the kitchen extension based on other people's designs I had seen on the planning portal. My architect literally drew them up and submitted them.

Mine included a vertical steel in the wall so I wouldn't have a pillar sticking out of the wall from the original back of the house.

My builder knew a structural engineer, he didn't even visit the property, went off photos (standard 1999 build of thermalite block and brick with cavity) and emailed us the details for the steels. Cost me £160 for that specification 5 years ago. Welcome to the North

I think architects can complicate matters. What does your builder say about the scope of the original plans? Any chance you can slightly reconfigure it to make the steels cheaper?

Given the size of your extension (and having done a very similar sized one ourselves) I would keep the roof lantern. You could ditch the bifolds and get standard sized French doors which would possible be cheaper. Have you looked at sourcing the doors and lantern yourself online?

We paid just over 3k for a 3x1.5 lantern but that was with a local window company. We could have got it cheaper elsewhere. Same with our doors.