House Spec - to send builders

liamolaighin

Hi there I was wondering if anyone has an example of a house spec they could PM to me or e-mail me. I need to get a detailed spec together to send out to tender. I have 1 example already but if anyone has an example where maybe it is stated what Energy rating is going to be achieved that would be great. Looking to build, standard cavity construction, insulated on inner leaf, tape windows etc. Trying to achieve A rating if possible going down this route to lessen energy cost long term. Prob going with boiler & rads as cant justify outlay on geothermal. prefer spend extra on insulation first day and have house thats cheap to build. Also trying direct labour route but need to get prices from builders anyway for bank. Detailed spec would be great help, also examples of prices from builders to give me an idea. Regards Liam

LoTwan

If you haven't already done it I would strongly recommend you have a preliminary BER done. This will cover a lot of the specs you have mentioned above (insulation, heating, windows etc) & will be worth the money you spend on it.

liamolaighin

I am thinking of getting this done. My brother is also going building less than a mile away and I could definately see the value of getting a self build energy report/spec done. I hear so many different views on pumped cavity walls (which i'm considering 150mm cavity), normal cavity with plasterboard on interior, and then ICF which my sister has recently build. Trying to balance a very good BER rating with low initial build cost and maintenance costs (i.e heating and esb for MHRV,solar panels, photovoltaics etc)

wirehairmax

If you are going to use direct labour then dont waste builders time preparing tenders. It costs time and money to price work and is very dishonest in my book to be using builders in this way. If you are using direct labour then do your own homework and prepare your own pricing document. Or else pay a QS or give a builder something for his time and expense to prepare a tender for you to use for your own benefit

Slig

If you are trying for an A rated house then get some professional help from an Architect, Engineer or Architectural Technician, many of the technologies involved in getting a house to this standard are pretty new to the market and will involve non standard building practices that differ from the normal of the last 20-30 years that many builders are comfortable with.
Even simple things like the enlarged cavity will impact on wall ties, foundation sizes, window cills and cavity closing details. The air-tight barriers and tapes will make the plumbers and electricians job more difficult and even small gaps or carelessness by a subcontractor can be difficult to find and costly to correct after the job is done.
I cant stress the importance of going for a set of construction drawings and documentation before you start building. This will mean everybody involved in the building is on the same page and your building can be accurately priced and programmed. They will more than pay for themselves by the end of the build.

galwaytt

liamolaighin wrote: »

Trying to balance a very good BER rating with low initial build cost and maintenance costs (i.e heating and esb for MHRV,solar panels, photovoltaics etc)

I appreciate where you're going, but there is a point where those two aspirations may come into conflict. Essentially, you will be building either to a specification or building to a price. (The former doesn't mean, btw, that it's an open-cheque build - you should always aim for value for your money..).

Practically speaking, an A-rated house is more expensive than a B-rated one, and a B more than a C, whilst a true Passive one would be more than all of them.

However, that's not the whole story - the provisional BER you get takes whatever building system type you propose to use, and it's performance, and here's the key thing: then applies it to your design and location - and it's only after that that you get your BER. So, simply saying building system X instead of Y gets you Z BER isn't so. There's much more in the BER than just the 'system', which only accounts for a % of the rating. The 'system' you choose will get you so far into the BER, but other factors have a big influence.

For all of these reasons, a provisional BER is a good idea - but it should allow you scope to use a number of build types to determine your rating, and in doing so use that (coupled with subsequent pricing) to help you make your build decision. I would make that point to your advisor at the start, so that you just don't get an emailed report to your desk which you have to then interpret for variables.

I've seen several BER's lately where the 'cut & paste' button has been very active in, so it's important that you would lay out, with your advisor, why you are doing it - to inform your build decisions - as distinct from just giving you a notional BER that ties you into any generic technology.

And remember, that even then, after that process, the ACTUAL BER will come from quality-of-build, otherwise it's all for nought.