How to ensure a home isn't leaky?

[Super_BQ]

he is the one that specialises in this because of his defect analysis skills.

Would his skills be sufficient in detecting water problems in newly renovated houses? I think from a seller's point of view, they would not welcome 'evasive' probing (in order to do a proper assessment) of such a house just to detect water dampness. I've seen some that use an infrared detector to assess how heat escapes from inside to outside the house. I'm sure there specific ones for measuring moisture in the walls? (But do they measure the already dried rotted wood from previous water damage?).

The problem with plaster is the material itself is no waterproof. Furthermore, the skin of any house expands and contracts with temperature. So the small fine (micro?) crack lines that you see all over a wall up close with plaster cladding is a major problem for letting water and moisture inside. This is why all new home constructions are required to have a "vented cavity" wall. But even still, I believe the best defense a house has against wood rot is to simply not expose it to water. So that means building long suffits (eaves) and use of permanent waterproof materials.

The concept that the masonry work is waterproof is flawed. It's porous and has a tendency to suck water from the ground. That is why a moisture vapor barrier is required by code around the concrete footing of newly built houses today (either black paint on asphalt seal or black plastic lining) Osmosis anyone?

[teamplayer2003]

Just make sure you have references of who ever is doing the building report. I wouldn't be scared of the poly homes. They are fine if they have been maintained. They need to be painted every 8 years max as the paint is a key part of the water tightness. But again it depends where you live.

In regards to the real estate new regulations are now in place so the HAVE to provide you with a building report if one is available and if they do no disclose any known problems they can be liable.

These type of regulations are coming into all parts of industry where some form of financial advice is occuring. This includes insurance, banking, finainace ect ect ect.

[Super_BQ]

In regards to the real estate new regulations are now in place so the HAVE to provide you with a building report if one is available and if they do no disclose any known problems they can be liable.

We've been discussing the case where if the building reports didn't find the leaky water problem in a house later on. Claiming liability from a previous owner is difficult or pretty much impossible. To make things worse, the age of the house can take it's toll. I overheard (but may be wrong) that compensation for home owners stuck with leaky houses are pro-rated to the age of the house. They're saying that if a house is 20 or 30 years old and starts to leak, well there's little or no compensation granted as the home would of had 'fair use'. It's the relatively new leaky houses (less than 10 years) present the biggest problem in compensation.

Building report or not, there's so many areas to check out. Buyers quite often don't have the time and $ to order LIM reports on every house they look at. If you truly want a house that doesn't leak - consider building new under current building standards.

[John Z]

What I've learned in the 2 years in NZ is that there is very little understanding of what is at the core of a leaky building; lack of ventilation.

When you make the walls weather tight, but forget that from the inside out a house produces moist (people are 70% water), and in the NZ climate there is a huge build up in temperature during the day and a huge cooling down towards the night, causing condensation, you need to make house temperatures "stable", including enough "natural" ventilation.

I have lived in an expensive, architect designed "contemporary style" house here, with the worst inner climate one can imagine... It was a "polystyrene house" btw, one that does not breath.

Since it is your own families health (!) you're dealing with, you have the responsibility to educate yourself so you know what you have to look for.

And that is also what makes this thread valuable!

[Super_BQ]

What I've learned in the 2 years in NZ is that there is very little understanding of what is at the core of a leaky building; lack of ventilation.

If this was the case, then I think my uncle up in Auckland (who's an architect) will be looking at mega issues on his home. He thermal sealed his whole house by using plastic lining vapour barriers (under the GIB) to ensure complete air tightness. I'm still compelled at how he convinced Auckland city council to approve of it. He told me that he convinced them 'mathematically' in terms of satisfying air flow and condensation issues. But from many believe, it's only theory on paper; in practicality, it's entirely different? or so is it?

Though we may see such air tight building practices in Canada and Scandinavia, they all have mechanical ventilation, and if that isn't enough in addressing air quality, 'heat recovery ventillators' are a mandatory requirement in new houses in Canada. So despite the nay saying I often hear like from my other uncle (the builder who's been in the NZ building industry for more than 40 years) he still can't grasp the concept of what causes leaky housing. The other day he (and i'm sure many Kiwis would believe) gave me the impression that if mechanical ventilation came to NZ homes, they would neglect it by not repairing it if it would break (thus sacrificing air quality). This is the kind of kiwi attitude that needs to change.

Going back to the example I was talking about with my other uncle in Auckland (the architect). He claims that NZ houses are rotting away from condensation NOT caused by the moisture developed inside the house (ie. from showers, kitchen, human respiration, etc.) but rather, cause from outside air moisture that gets trapped in between the timber framing by lack of proper insulation. How he combated this problem was by simply control thermal bridging and keep the framing of the house isolated from the inside and outside by using mass insulation. He actually used the example of how fridge/freezers are insulated. Arguing that if you think condensation is a problem because of the huge temperature difference, then why is it that the inside insulation of a fridge does not condensate? And surely the temperature inside a freezer is great enough to cause condensation. If you built a freezer like how you build a wall in NZ houses (air cavity, Tyvek house wrap or building paper, timber framing, and use only fiberglass insulation between the wall studs), you may find the freezer will condensate and water dripping on the ground.

When you make the walls weather tight, but forget that from the inside out a house produces moist (people are 70% water), and in the NZ climate there is a huge build up in temperature during the day and a huge cooling down towards the night, causing condensation, you need to make house temperatures "stable", including enough "natural" ventilation.

But you have to remember that energy efficiency in keeping heat inside a house is a function of the thermal transfer of energy that goes outside (either through bridging or through air gaps). The more air gaps you have (to promote natural ventilation), the MORE costly it is to heat your home. I believe this ideology was given up (the use of breathable walls) in Canada 50+ years ago. The move to an active controlled house proved more comfortable and more healthy (use of central heating ventillations + HRVs). I also don't believe NZ's climate is that unique. Many nations experience the same extreme temperature changes too and their houses don't appear to rot. The extreme challenge is how to keep the inside room temperature say 20C when outside is -40C ? NZ houses have a tough time reaching 18C when it may only be -5C in the winter months.

[John Z]

If this was the case, then I think my uncle up in Auckland (who's an architect) will be looking at mega issues on his home. .............

Your comparisson with the fridge BQ is failing because you're comparing a continuous situation with a situation that constantly changes.

(If you don't see this point I'll explain further)

The typical way Dutch houses are built is like this:

An outer layer that can breath (mostly brick, nowadays also (partly) wood), then an air gap of about 6 cm. then your insulation, attached to the structural inner wall.

Since in the Netherlands houses are being built MORE air tight, active ventilation is installed, mostly including an energy regaining installation. What is advised over and over however, to use the ventilation slots in the window frames, but often people forget to use them, because they think that way they loose energy.

But without the ventilation relative moist builds up, causing the need for more energy to heat up to a certain room temperature.

Could you explain the typical schematic construction of walls in Canada, if there is a typical way of doing that?

[John Z]

...............
Going back to the example I was talking about with my other uncle in Auckland (the architect). He claims that NZ houses are rotting away from condensation NOT caused by the moisture developed inside the house (ie. from showers, kitchen, human respiration, etc.) but rather, cause from outside air moisture that gets trapped in between the timber framing by lack of proper insulation..............

In this context, considering a rotting frame he is right, as far as it's moisture that is trapped.

[Peterrdharris]

Hi, the leaky house issue here is an interesting one. I am a building surveyor and have a business advising people with such houses who are referred to us by HOBANZ. It is a very significant issue, however, There are a lot of would be leaky homes that simply aren't leaky. Most houses built in this fashion will require increased amounts of maintenance, like repainting for example, and over the long term, some that are ok now, will really need some more significant repair and reclad work once they get to 15 years old or more.

The secret is making a decision on location and then working out what risk you are prepared to take and weighing it up. A lot of people are getting an exceptional deal buying monolithic clad homes. I live in one!

If you let me know where the house is that you are looking at, we could do a quick drive by for you if that was helpful to give an overview, or flick me the website link for it.. Good luck!

[Kea]

Many thanks Peter. I did more research into plaster homes and decided it was a risk too far for us. I think a dual market has developed in this area with many people unwilling to look at plaster. I had an email update from an agent who suggested at 4/5 people are not willing to get out of their car to look at a plaster home. So if you are intending to live in a property for 10+ years they can be reasonable buy. But, if you want to freedom to shift they may not be so sensible, regardless of structural issues which may or may not appear.

Looking at sales stats in this area I recently saw a monolithic clad sell for $450,000. C.V of $750. You have to feel for the owners in this situation.

We've bought a 195's weatherboard and move in Feb.

[hoping2win]

stay away from monolithic cladding, in the early days it would sag and come into contact with the ground. Some leaks are impossible to detect except by destructive methods. You can get air tests done to detect any mould spores, http://www.consumerbuild.org.nz/publ...alth-risks.php