There's A 'Stranger' In The House!
Posted 06 April 2015 - 09:21 AM
I'm very much a novice to this sort so bear with me.
I am about to order an MBC house, (can I say that) and would very much appreciate your help over the next few months.
I have met Jeremy and Rooskie and they have been very helpful, thanks gents, but don't want to become a pain in their nether regions with constant requests for advice.
So here's the first one.
The person doing my building regs has never come across a Passiv house before and his draft building regs talks about trickle vents and omits MVHR. I understand that trickle vents are a definite No No but wonder if there is a standard wording that he could use which would cover the ventilation/MVHR aspect?
Posted 06 April 2015 - 09:28 AM
It was hard work finding someone, but in the end all my design and BC work has been done by an architectural technician who knows a lot about passive houses.
Posted 06 April 2015 - 09:57 AM
The building regs bit for MVHR is pretty straightforward. Initially there is nothing that needs doing in the application, just a statement that the house will have an air leakage rate well below building regs requirements and that whole house ventilation will be used in accordance with Building Regs Part F specifications.
Once the house is built and tested for air leakage, building control need two things. Firstly they need a copy of the air test certificate (this will be provided by MBC as a part of the package, so all that needs doing is forwarding it on to building control). Next there needs to be a compliance report, provided by a competent person, showing that the requirements for whole house ventilation in Part F have been met. This is straightforward again, but depends on how you're fitting your MVHR. If you're getting a design, install and commission service from a supplier then they should give you the required report showing the ventilation rates achieved and that they comply with the regs, in which case you just forward this to building control. That's it, job done.
If you're going down the DIY MVHR install route, then you will need to provide a report showing that two conditions in the regs have been met. This requires an air flow meter and a bit of maths, but is tedious, rather than difficult. Firstly you need to set up and balance the system as per the manufacturers installation instructions.
Next you need to set the MVHR to trickle mode (usually the lowest fan speed) and, having made sure that the fresh air in and extract out flows are balanced (which is a part of the installation) you measure the actual flow rates coming into the house. The best way to do this is to put a flow meter up against each fresh air inlet in turn, let the reading settle, and record the average reading, ideally in litres/second, but often flow meters are calibrated in cubic metres per hour, so you may need to do some maths to convert the numbers. Add up the fresh air inlet flow rates from every inlet and that gives you the whole house ventilation rate. This has to be higher than 0.3 litres/second x internal floor area of the house in square metres to pass the regs. The chances are that you will find that the trickle flow rate may well be a lot higher than this, in which case you can turn it down later to prevent excessive ventilation.
The second part of the test is to measure the extract rates with the MVHR set to full boost speed in the relevant extract rooms. You do the same procedure of measuring the flow rate with the meter, but this time on the extract vents in the rooms that Part F sets the spec for. The kitchen extract on full boost has to be 13 l/S or more, the bathrooms and utility rooms have to be 8 l/S or more and the WC has to be 6 l/S or more (if it's stand-alone and not in a bathroom).
You can borrow or hire an airflow meter and do the test yourself and write a short report for building control, as there is no definition of a competent person for this in Part F. Attached is a copy of my report submitted to my BCO showing compliance with Part F that might help your building regs chap understand what's needed. Note there are some other minor points in Part F, like the MVHR having to be fitted so that it is accessible for servicing and filter changes and these are addressed in the report with photos and a short statement.
Mechanical Ventilation and Heat Recovery system Test Report.pdf 190.24K 24 downloads
Edited by jsharris, 06 April 2015 - 10:04 AM.
Posted 06 April 2015 - 10:00 AM
As Dave says are you sure he is the right man for the job.
Edited by joiner, 06 April 2015 - 01:34 PM.
Posted 06 April 2015 - 01:38 PM
As you've met two members already, perhaps invite your guy to drop in on Jeremy's build?
Posted 08 April 2015 - 10:32 AM
We are The Mitchells and currently live in Bicester, Oxfordshire. We've been trying for several years to find and buy a plot of land but prices round here are too high or in terrible places. We did find a plot in 2008 which was expensive but I was getting desparate by then so put an offer in. However, there was an electricity cable strung across the site, right through bedroom 2 and, while the Electricity company did plan to put it under ground, they couldn't give me a specific date. After humming and hawing for a while, we dropped out and two months later, everything financial crashed and we'd have been in deep trouble. The cable was eventually moved three years later!
So after nearly getting our fingers burnt, self build was put on the back burner for a while. However, I have been still looking and was thrilled when in early 2013 we heard Cherwell Council were planning to buy the local MOD site and convert it into 1800 self build plots. We immediately registered our interest and I went into over drive researching build methods, going on self build courses and reading every self build book and magazine I could find. Initially the internet site (Gravenhill.org.uk) said plots would be sold at end of 2013, that became early 2014, then late 2014, and now its late 2015!
However, things do finally appear to be moving and we have just heard there is to be an information day next month (March 2015) when hopefully we'll get to hear about plot sizes and costs. The infrastructure should be starting by the end of this year with some of the self builders moving onto site early 2016. So while it has been very frustrating waiting for the plots to be sold, we are hopeful it will be worth waiting for. Planning should be fairly straight forward as its the council's development and they appear to be quite flexible about styles. And by building alongside others in the same boat (or street!) hopefully we can share knowledge and stresses and maybe even purchasing power?
Anyway - we only recently found this site so have been busy reading all the blogs and getting as many tips as possible. Thanks for sharing and I hope its not too long before we can do the same.
Corrine and Mitch.
Like yourself, my wife and I are looking to build at the Gravenhill site. Perhaps we can club together some like minded people and share ideas/resources so that we can achieve our dream house faster/cheaper/better?
Posted 08 April 2015 - 01:34 PM
Posted 08 April 2015 - 08:59 PM
Posted 09 April 2015 - 06:10 AM
Posted 09 May 2015 - 09:50 AM
Just a quick intro..
I'm glad to have stumbled across this forum at such an opportune time for us because, having been searching for some time, we (hope!) we have finally found a plot on which we are looking to put a Carpenter Oak style house.
Living in North Bedfordshire we are severely restricted by the local settlement areas where any build opportunity has long ago been grabbed by developers and then rammed with Potton Style timber frame boxes. Yuk!
SWMBO and I have fully refurbished / extended / improved 3 houses in our time but now the kids have finally flown for good and our ageing parents are (somewhat sadly) no longer a problem, we have reached that time in life where we can do what is best for just us.
Looking forward to reading & learning from real experienced self builders.
Edited by Eyefor, 09 May 2015 - 12:20 PM.
Posted 09 May 2015 - 09:57 AM
I wish you well with your plot and hope you get it and it's what you want.
If you look at the blogs you will see the trials and tribulations of other self builder, some who have now finished or nearly so, and some in the early stages.
Posted 10 May 2015 - 09:54 PM
So are you looking to build in the same area? and are you after building a low energy home?
Posted 18 August 2015 - 02:54 PM
Edited by joiner, 18 August 2015 - 03:53 PM.
Omission of "am" corrected.
Posted 18 August 2015 - 03:56 PM
Just choose an appropriate category and post away with your questions. It's what keeps these places going and, by the way, you'll find a fund of infinite patience here.
Posted 26 September 2015 - 08:28 AM
We have an almost south-facing 1930's bungalow on the Hants/Wilts border. We have planning permission for replacement roof with 2beds and bath.
But because of the passage of time and interest in renewables and all things eco have begun to find out about SIPS for the roof. Then we started wondering about the benefits of knocking down and starting again. So a lot on the forum about SIPS and MBC Timberframes.
So currently more investigation going on. Loads of reading and head scratching.
Posted 26 September 2015 - 09:46 AM
It is pretty hard work trying to understand all the nuances of the different build systems, not helped by quite a few suppliers not being fully aware of some of the potential pitfalls a low energy house presents, particularly with regard to things like cold bridging and interstitial condensation risk reduction. One snag is that the UK building industry is very conservative and slow to adopt new methods of construction, and when they do, they sometimes fail to grasp some of the fundamental changes needed to things like foundations and the fitting of doors and windows. Things are improving, but it can be tough getting hold of good, independent, advice. I suspect this forum has done a fair bit to bring about greater awareness of some of the issues, mainly because we have a very wide range of knowledge, experience and skills across the membership as a whole.
Posted 26 September 2015 - 06:55 PM
I've found a disused well in the garden. Disguised as a flower feature. Having dug out earth and weed mat I've found a load of rubble. Might it be worth attempting to remove more rubble with a view to finding a water source (for the garden, not drinking. Though a neighbour tells me she was using her well when she first moved in 30yrs ago). Is there a safe way to do it once it gets below ground level (thinking about gas etc sinking into it)?
Or is the safe route to get it properly and securely blocked?