Prefab Extensions

rajanm

Hi all,

We're interested in getting our kitchen extended - we don't have a massive budget so have been looking at alternatives to the traditional brick extensions.

We have ruled out a conservatory as it seems heat loss could be a major issue in the winter.

One thing which caught my eye was the idea of a a prefabricated extension - constructed off site then bolted on to the back of the building. Some of these look pretty impressive but I have a couple of questions:

1. Would there be a significant cost saving with this approach?
2. Are there mortgage issues with having a prefab extension as part of the house (some of these, as far as I understand, are primarily built of SIPS panels)?
3. Does anyone know of any installers in the South East? All I can find are manufacturers but no details of actual builders.

Thanks

Rajan

Furts

Whilst I am not a conservatory supporter, they do have a role. Extra floor space on a tight budget can be achieved and they will not be too cold in winter if designed and specced with an element of thought.

MiL has a new one and it is north facing. It can be used all year, but in the middle of winter the outside is so gloomy it becomes not cosy to sit in. A sitting room can feel better.

Also for those on a tight budget the option of self build, or part self build, or family help should be explored. This means a brick extension that you refer to. Indeed, with care one need cost no more than an economical conservatory if one is savvy, and contributes to the work.

I would consider all this before any notions of prefab extensions. Here I have no idea what you are looking at, but my default position would be wary, or avoid like a plague.

Ozzuk

I've been looking into SIPS and they appear fantastic. Probably better if your house is currently rendered as they can often match the finish. The benefits seem to be less foundation requirements (lighter load), vastly quicker onsite build times (days instead of weeks) and more inside room as the walls are thinner but often better insulated. I just googled SIPS installers and found several. One of my friends said his neighbour just had a SIP extension and it went up very quick.

So I've no direct experience (seem them used on a lot of house building programmes though!) but they look excellent and I wouldn't hesitate to consider them.

I've decided not to proceed on my house purely because its a renovation project and it won't add enough value to justify outlay (due to current house design).

Doozergirl

SIPs are point blank more expensive than brick and block. You still need to conform to building regulations if your extension is integrated and the extension will need to be tied in and the foundations balanced so that there is no large discrepancy in how the extension and original house behave - this is likely with two very different building systems. You still need to address all the heating and electrical elements, plastering etc as well as glazing. There is absolutely no financial benefit to be found.

A garden building should be separate to the house and this could work out cheaper as there is less, or even nothing to comply with. It's why conservatories are cheap. Compliance.

rajanm

Any thoughts on an Orangery? Would this be cheaper than a standard extension?

Furts

rajanm wrote: »

Any thoughts on an Orangery? Would this be cheaper than a standard extension?

Your original post said you had ruled out a conservatory. Whilst a conservatory is totally unsuitable for a kitchen extension - which is what you say you are after - it is suitable for winter use, which is where we differ.


Why do you now think an orangery should be suitable? This is just an over rated, over complicated, over expensive conservatory to my mind. Leaving my judgement on this aside, because this is your choice, this is still equally unsuitable for a kitchen extension.

System

there are some instances where sips kits can be used to save a bit over traditional construction, but it doesn't really work out on an extension in my experience.
many ways to skin a cat but the reality is on extensions the new fabric isn't going to offer up any huge savings over the other technologies. With a single storey especially, you will have to pay a builder to do foundations, walls below dpc level, any slappings into existing openings etc so to get them to do a few more courses of brick/block to go from dpc to eaves level isn't a massive addition (or potential saving opportunity)