Proposed double storey side, Part single part double rear, complete render

[Designs.3DR]

Hello all,

I have been lurking in the background for a while now and have decided since I am about to embark on my own large extension I should try and document as much as possible.

I am planning on knocking down the side garage, and rebuilding it wider with a floor above. The rear will be a part single and part double storey extension.
It will all be built in blockwork with the intention of then rendering it all at the end.

A little bit about me.... So i have a BSc in Architectural Technology and a BSc in Building services design. I have worked for consultants and contractors on projects such as schools, hospitals, residential,. commercial and the rich and famous.

I started my own company about 5 years ago providing architectural plans for residential homes so I have used my skills to do my own planning. So far to date I have spent £206 on a planning application, £43 to discharge a condition, £400 on structural plans (mates rates), Party wall agreement - free and £1000 on the building regs application.

Total cost before I can put a spade in the ground is £1649.
Bear in mind that is based on getting the party wall agreement for free as i do work for a surveyor and also discounted structural plans as I give the structural engineer a lot of work.

Onto the house. So we brought a 1950s home in the south east. It is a detached house with space either side, 2 doubles and a box room so pretty standard stuff. We plan to knock down the garage to the side and rebuild it wider with a 1st floor extension above. On the rear will be a part single and part double.

Below is the existing and proposed floorplans.

Construction is due to start at the beginning of July. Prior to starting we will be insulating the old roof, cavity insulation, PIV installation and a new boiler.

We are adding around 135m2 of space with about 80m2 on the GF and 55m2 on the first floor. The shell will cost me about 70k (mates rates). The builder will be doing the demo, foundations, floors, drainage, walls, roof (replacing old felt and battons and retiling the old roof as well), replacing all existing windows and aswell as all new windows on the proposed with 2 bifolds, 1x rear door, front composite and a flat roof skylight. Steels and knock throughs and all skips and site clearance.

Internal works will be left to me.

any comments on the layout feel free to comment. There maybe things I haven't thought of.

 

[kingandy2nd]

Looks good mate, nice job with maximising the layout.

That’s a very good mate to do all that for £70k. Feels like the materials would cost more than that!

Have you considered the drainage? I see the downstairs toilet is below the original bathroom but there’s no manholes on the plan. Moving drains/manholes will add cost / complexity if needed.

Cheers
Andy

 

[Murdochcat]

How much do you think you’ll be spending on the work you do and how much is your contingency fund?

£70k sounds VERY low unless it’s all cash,

 

[Designs.3DR]

I have the drainage on another plan but the upstairs toilets will have a SVP in the alleyway where there will be a inspection chamber and to the right of the utility room will be a manhole where it then runs off towards the neighbours.

70k will be for the shell. Internally i am estimating about 40k (not incl kitchen.) UFH will be to the large kitchen/diner and play room. Rest will be on rads.

The builder gets a lot of work from me so i dont actually think hes making any money off it. Rendering I have had quotes around the 16k mark for monocouche and silicon based but that will be a job for next year funds permitting. Next year we will do the landscaping.