Trying to come up with some rough costings

racersedge

Hey folks of this forum, first time visitor and poster here so please be gentle! I apoloigise for the long post. Maybe put the kettle on! Feel free to call me nuts by the end of this.

Have long considered the idea of getting an extension done to the house and this issue has only become more pressing since the arrival of a child early last year. Our kitchen in particular has a terrible layout (it was the one that was in the house when we bought it four years ago) and while we have considered just renovating that, my thinking is think forward and build the extension to incorporate it to add the extra room - as opposed to renovating the kitchen now and then down the line having to try to adjust it to take in a future extension.

I have had a few 'all in one' building companies out to assess it and gotten a quote or two for doing all the work from beginning to end. I realise that to try to go and get each part done individually might be more cost effective, but I honestly know little around all this area and reliant on others who have expertise.

So yeah, currently hashing out all the ideas, which is where I come to the good people of boards for some help. An idea thrown out at me by a family member was that instead of doing the old fashioned bricks and motar extension approach, was to look into getting an outdoor living shed-style setup and attach it to the house. Visited a showroom of one such company and looks grand and gotten a quote for it (they basically just come in and build up the frame/windows/doors etc).

So I have that quote, but I don't have a total outlay to look at, which is where I'm looking for some rough costing (I realise that for more specifics, I need to contact a range of people but I'm hoping to get a rough estimate of potential costs here to add the maths together before that time consuming process comes in.)

What I'd need to get the done:

To start, the drains would need to be sorted as any extension would be on top of pre-existing outlets. This needs to be done regardless as we have had fierce trouble with our position on the sewage line. We have had issues with it overflowing at peak times of the year (or with weather like today) through no fault of our own. We get everyones else... well, you get the picture.
So getting that moved/widened/deepened or whatever needs to be done has on the agenda for some time.

Foundation for an 8m x 4.5m done out the back of the house. That would involve knocking down the existing shed (moving out the boiler that is out there to set it up elsewhere) and leveling the ground out nice and flat so that the shed (should I just call it a prefab building? Sounds a bit more homely than shed) to be placed on it. Levelling of the garden would be required for some landscaping to ensure no issues of drainage etc.

Lower part of the house would have to be, for lack of a better word, smoothed out/sanded down (told you I was a rookie at this stuff) so to allow for the shed/prefab building to be attached to the current back of the house. Would be looking to remove the wall under the kitchen window to create a new entry-way in to the new extension area as well.

With the installation of the shed/prefab building is sorted by the company that supplies. But still would be needing someone to move the external drains from the upstairs bathroom to compensate. Heating would need to be run into the new extension (probably talking about tearing up the pre-existing kitchen floor to run out such pipes). Our hope would be to have a small bathroom within the area as well just to have one downstairs.

Within the new extension building, would be needing to get the walls plastered, plumbing and electrical work done up into it and up to snuff and a floor laid. Some of the non-essential decorating can wait/be done by ourselves, but just to have this area set up to be habitable.
Final bits would include moving the current oil tank back further and having a small little attachment shed put together to store the boiler.

Chances are I'm forgetting something in here too.

Y'know, when I write it all down like this, it seems like an epic amount of work to be done. Probably a bit mad to consider it but this is going to require having to take a loan out to do. If it can be done and done right, and save money compared to other methods, then I want to investigate it fully before we make a final decision.

I appreciate the time and energy anyone takes to read this, let alone comment and give me some rough estimates on what the total outlay of such work would be.

Regards,

racersedge

looksee

You seem to have a decent grasp of what needs to be done. Just on the point of the boiler, if it is to be moved it will probably be worth looking at how old it is and whether it might be worth replacing it. New outdoor ones are becoming much more appropriate and have their own waterproof 'shed'/protection. If you are replacing the oil tank consider getting a bunded tank to avoid spills. This will of course add to the costs (probably around 5 -6k, but this is what happens when you start disturbing things!

If the sewers outside are main public sewers the local authority may have some responsibility for them, you need to talk to an engineer/surveyor - in fact it would be a good idea to do this anyway as this is one area where you need to get it right first time, and there might be other things that you have not noticed. You really should have some drawings especially if you do the job with different trades so there is no ambiguity about what they are being asked to do. This is one area where some outlay can actually save a lot of headaches and money in the long run.

You could make a complete list of everything that needs to be done and go to a quantity surveyor. They will probably require proper drawings to give you a clear idea but they can do what my QS described as a 'quick two page job' for a reasonable fee, which will give you an idea of the kind of numbers you should be aiming for.