Cost of small lean to extension

[naboo]

I am looking to build a small "lean-to" extension, 4m by 1.8m, to the side of my wife's house. The area of land on which it will be built is currently a concrete path (poorly built) and grass. There is currently a large double window in the area where I will build the extension which I will have removed and the concrete below taken out to provide access to the new area (limited access required, will be adjacent to our bedroom to create an area for wardrobes and dressing).

Basic construction, I need foundations built, the outside ground raised approximately 60cms to meet the level of inside the house, floor tiles, bricks and cement walls, steel roof structure with clay tiles, foil lined foam insulation in the roof and a gypsum ceiling, then painted inside and out. Complication, I'd like a skylight in the roof to allow some light in - the bedroom currently has two large windows that catch the afternoon sun making the room hot, but the second is onto the car port and so the bedroom may get a little dark without some light entry.

The builder will be my wife's cousin. He leads teams on house builds and built my wife's parents' house - quality is generally very good. I've had work done by him in the past and agreed to pay him 700B/day and a partner 400B/day where required. I then pay for the materials. This usually ends up messy as he's family and so days of work don't happen as family outings get in the way and we agree on a suitable payment at the end. I'd rather agree on the fee at the beginning, all inclusive of labour and materials and let him get it done within his own timescale without a daily pay rate - I don't want to screw him over, I don't want to be screwed over, and I don't want any trouble which has been close in the past when he went off to the temple for the morning, again.

I know when I approach him, he will say price is up to me. I'm thinking approximately 25,000B all in, but may be a little under as I don't know how long the job will take and have no idea how much 8sqm of tiles for floor and roof will be. How much, best guess?

[PattayaPhom]

Firstly forget a skylight, you will have nothing but problems with leaks. Labour at 700 a day is generous and with a gofor at 400 your budget will be somewhat more than the planned 25,000. I would estimate at least 2 weeks to complete with full working days. Building materials have increased considerably in the past 3 years. Raising the floor level 2 feet with cement will cost approx 4k alone if ordered by truck. 40,000 is more realistic. Ive just had a basic 5x6 outbuilding and that came in at around 75K. but no tiling, ceilings, basic blocks at 4.5 Baht, cheap roof tiles and the labour a lot less per day.

[naboo]

Thanks.

My wife thinks 10,000B, but her standards aren't mine and she doesn't have a clue.

I pay him 700B a day because he's good, he's a leader, thinker, knows what he's doing, and he makes sure anyone who works with him does a good job. He contracted by a large developer and has lead teams on many builds - no big manager or anything, but far better than your average guy.

If you're saying two weeks, I'll offer him 14,000B labour (1000B a day for him+1 for two weeks) for the job and tell him he can use that to employ any additional hands as and when he needs. I'll buy materials - I get 30kg bags of sand and gravel for 50-60B a bag (fill it yourself off the heap), lots of builders merchants still cheap up north. Instead of a skylight, I'll stick in some of those glass (??) bricks - the extension will be getting to within a metre of the land perimeter and the neighbour has OK'd the build, but no window, glass bricks a good compromise.

Will budget 40,000B but hope it won't get to that much. Keep the costs under my watch.