Help Self Build

Lollyy

hi there, I am new to boards and new to the building thing so apologies if this question has been asked 1000000 times.
We are self building a house but are not sure whether to go timber frame or block. Cost is a big issue as we need to keep the cost down but we also need to achieve an A3 rating on the new build.

My other question is the we have been told that we need to fit a heat recovery system but I really don't like the idea. I have been in a house that has this system fitted and I found the air to be very dry and stale.....was i imagining this!?

Any advice would be great as I am clueless!

Metric Tensor

If you think the house is dry and stale with MHRV you should try building a modern air-tight house without it! It would be stuffy and overly humid!

In my opinion in a house that is as air-tight as required by the current standards MHRV is an absolute must to keep the environment healthy and pleasant.

If you find the air stale, like in all house, you just open a window!

Lollyy

Thanks so much for the reply. I thought if you opened a window with the MHRV system though that everything goes out of sync and the system has to work harder to maintain a temp? is that a stupid question??

Gumbo

Who is overseeing your build?
They can carry out a cost analysis of Timber V Block and the associated BER details to see which will cost more to construct.

*Of course, the above is on the assumption you have engaged somebody to oversee the works and that you will have to pay them as nobody will do it for free.

Lollyy

We have an architect technician who is overseeing things from this point for us. I need to have a meeting with him to see if he can give us the costings for timber v block.
Is this something that you would expect him to be able to give us?

Calahonda52

Lollyy wrote: »

We have an architect technician who is overseeing things from this point for us. I need to have a meeting with him to see if he can give us the costings for timber v block.
Is this something that you would expect him to be able to give us?

More importantly, are YOU prepared to pay him for doing the work required to a standard of accuracy that YOU will be happy with.

Who TOLD you you have to go MHVR
If you have only recruited a professional now, I trust the project is really a DIY self build.

Who came up with the A3 requirement.

Re the stale and dry experience, how do you know the system was properly "done" from start to finish and was not a beermat design job:

Some recent research findings
Summary: A national study analysed the performance of mechanical ventilation systems. Ventilation systems with natural supply and mechanical exhaust ventilation (MEV) and balanced mechanical supply and exhaust systems with heat recovery (MVHR) were investigated. Surveys were performed in 299 homes, which included visual inspections and measurements of ventilation rates per room and installation noise levels. An additional survey regarding perceived indoor air quality and self- reported health was completed per household.
Observed findings were:
 In 48% of the dwellings with balanced mechanical ventilation the total air supply rate was insufficient (<0,7 litre/s/m2), while the air supply rate in 85% of dwellings was insufficient in one or more rooms in comparison with the Building Code.
 Total air exhaust rates were insufficient in 55% of the dwellings with balanced ventilation and in 69% of the dwellings with mechanical exhaust.
 The exhaust rates in one or more rooms did not comply with the standards in 80% (MVHR) and 76% (MEV) of the dwellings.
 Noise levels are higher than 30 dB(A) in one or more bedrooms in 86% of homes with MVHR in the setting in which the ventilation system is providing a sufficient ventilation rate (>0,7 litre/s/m2) in many dwellings (or in the highest setting if the ventilation rate is insufficient).
 High noise levels are in part caused by incorrect placement of (flexible) ductwork, for example sharp bends.
 In most cases, the ventilation unit is placed at position that will increase the chances of ventilation noise (53% of MVHR and 67% of MEV).
 Silencers are not properly installed on either air supply or exhaust duct (66 of MVHR).
 Ductwork is not properly installed (48 of MVHR and 40 % of MEV).
In many instances where mechanical ventilation systems show problems, the installer, the contractor, the developer, the architect and the end-user are all to blame. The underlying problems seem to be improper design requirements, a lack of quality assurance, lack of inspection and enforcement of the building code and a too small budget. Another potential factor is the lack of coordination between the design team, the engineer and the installer, leading to contradictions on site that result in compromised installations.

anoble66

I was in a A3 rated house last April / May time frame, they had moved in but the MHRV was not yet commissioned / active. I can tell you the air was very still / stuffy in that house, windows were open in order to improve the situation. But with windows and doors closed it was a strange sensation and not one I would like personally.

I currently live in a timber frame semi-d built in 2005, no MHRV system but C1 rated so nowhere near as air tight as modern builds. What I can say is it overheats in the summer and loses heat quickly in the winter. I know a modern air tight timber frame home would be totally different but it was enough to put me off and I am going block build this time.

Lastly, I would not hold out for much of a price difference between timber v block. In fact when I was looking into it a while back timber frame was coming in more expensive. A QS is your best bet for this comparison once you have a build specification.

But all this is just my experience. Don't make decisions based on forums. Get the right professionals informing you and you will not go far wrong.

Best of luck with your build.

Dudda

Lollyy wrote: »

We are self building a house.....Any advice would be great as I am clueless!

Why are you going to self build if you don't have any experience? You could end up making mistakes or having to hire someone to help you which could end up costing more. I'm worried about your knowledge and experience for taking on such a large project.

Gumbo

Lollyy wrote: »

We have an architect technician who is overseeing things from this point for us. I need to have a meeting with him to see if he can give us the costings for timber v block.
Is this something that you would expect him to be able to give us?

I would only expect him to provide what you paid for tbh

mike_2009

You can send the plans to one of the timberframe specialists in ireland (google away) and they will get you a quote for the timber (factory built) and erecting it - you still need a builder to strip the ground for the foundation and look after 1st and 2nd fix etc but it gives you an airtight, weather tight structure very quickly once windows and doors are installed and you just need a roofer. The inside can be fitted out at your leisure. Even if you don't proceed the price gives you a comparison to block built right there.

Regarding mechanical ventilation, if you're still thinking about this in October/November watch out for the near zero open door day event where several people who own energy efficient houses open their doors and you can judge the air for yourself and ask questions. Google "nzeb open door".

Best of luck!