How to Interpret Building Inspection Reports

Are you confused with your building inspection report?

Do you actually understand what your property inspection results mean?

There are some very good building inspection companies in Auckland, Wellington and Christchurch (and everywhere in between), but the reports some inspectors supply can sometimes confuse the buyer with ‘builders’ terminology that you may not understand.

Normally you would call the building inspector with questions, but if they aren’t available for whatever reason, and you want to know right now what they are talking about in the report, then take a look at the glossary of building terminology at the link below for a possible explaination.

For example: If your report says “The leak captured in this thermal imaging report above master bedroom window could be due to a missing head flashing, or miter joint failure in window on 2nd floor directly above this area”… do you actually know what this means?

Here’s a glossary of terms used by builders and home inspection companies:

Interpret Building Terminology Here

The ‘complexity’ of our infrared leaky building inspection reports are written in accordance to the buyers level of building knowledge. If you know nothing about how a house is built, or aren’t sure what certain parts of the home are called, then you will still be able to interpret our reports.

Locating Leak Damage on Wall Frame Stud

Moisture or leaks infiltrating your wall frame studs can cause problems, regardless if the timber is treated or not.

One of the most common questions I get asked when someone calls me for a pre purchase thermal leak inspection, is “Should I worry about getting a leak/moisture test because the timber is treated?”. YES!

For example: Lets say the home is only 4 years old (Built to the new building code… treated timber on external framing), and there was a window joinery failure from day 1. If the window has been getting hit by wind driven rain on a regular basis, then ‘gradual leak damage’ could occur on the timber framing if the water didn’t get out through the cavity. The same scenario would apply  for pre 1992 built homes… in fact, the timber framing will rot no matter when the place was built if enough water gets to it.

Here’s an infrared thermal imaging leak photo of a wet wall stud in a home with treated timber…

The darker wall stud is a different temperature... couldn't be seen on the wall as indicated in right hand image
The darker wall stud is a different temperature... couldn't be seen on the wall as indicated in right hand image

Locating a leak in one section of a wall can be simple with the right leak detection equipment. If you have any doubt at all in the home you are buying… get it checked for leaks, because the home owner may have fixed the source of the leak, but not the damage it caused along the way.

The benefit of our thermal imaging camera, is that ‘tricky’ vendors who paint over walls and ceilings in an attempt to hide leak marks will get caught out, because if there is moisture on the gib at the time of inspection, no paint will hide it, as it will be a different temperature… which is exactly what our infrared camera will detect and locate.

Moisture Meter – Measuring Moisture Content of Wood

We have a serious moisture problem in this country when untreated timber comes into the picture!

The moisture content within timber has a very important bearing on the uses for that type of wood. Having a good understanding of how moisture and leaks effect timber types is therefore critical to determine utilization. Moisture meters are the fast way to read moisture levels in wood.

Here’s a quick lesson about wood moisture, how it works in timber… and why we have leaky homes and leaky buildings in NZ:

The makeup on wood is best described as 1000’s of tiny cells… and within those cells are cell walls and cavities. Heartwood and Sapwood in their raw form (freshly cut) are saturated with moisture, and you may have noticed this yourself when you cut down a tree. In between the saturated cells are very small spaces of air. Once the wood has been cut, and the drying out process of the timber begins, the first part of the cell to loose it’s moisture content is the cell cavity, and then the cell wall.

Important to understand: Once the moisture from the timber cell walls has completely evaporated and the timber itself has somewhat shrunk in the process, the woods moisture content will then be in equilibrium with its surroundings (EMC – Equilibrium Moisture Content).

Once the timber framework of your home has been put in place by the builder, from then on its integrity and life span will be subject to the variations in surrounding relative humidity (and to a lesser extent, temperature). In general, most countries around the world including New Zealand, will have wide variances in humidity between winter and summer months, therefore the Equilibrium Moisture Content of the timber will affected (swelling and shrinking) if it wasn’t originally dried to the average moisture content is will attain in use. That’s why moisture meters quickly help us to determine if the timber is either dried out, or wet.

Are you starting to get the picture about why the high moisture content in untreated timber is causing major issues here is NZ with leaky buildings?

How does temperature affect moisture readings?

Most companies will initially calibrate their moisture meters around 19 -21 degress. The problem with people who aren’t experienced and don’t know how to use a moisture meter correctly, is they aren’t aware of how to add or subject readings based on temperature corrections. The basic rule of thumb, is that you subtract 1 from the meter reading either way per 5 degrees in temperature variance (this only applies up to 70 degrees in temp). The best moisture meters for sale in NZ will have this correction feature as a function.

You should have knowledge about the different timber species used in NZ buildings prior to arriving at a benchmark moisture percentage to work with. Treated and untreated timber will require adjustments. Untreated timber will actually give the most true reading because there aren’t any chemical preservatives to throw the moisture reading out.

We use a moisture meter to test NZ houses daily, and it works out cheaper for us to do the moisture inspection for you then buying one for yourself. 

(Source: Some of the above info was provided by NZ Forest Research Institute)

Cheap Leaky Buildings for Sale

If you are seriously in the hunt to buy a bargain property, just be careful that you don’t actually get more than what you bargained for!

In this case, a ‘first time’ unexperienced buyer of leaky buildings hired me to moisture test a property after he had already payed a non-refundable deposit (auction).

If you see any advertising telling you about cheap leaky buildings for sale, then please proceed cautiously, because some leaky buildings leak so badly that they are beyond your standard re-clad to fix up.

Recently I did a home inspection for a client who was aware the home had moisture issues… it even stated that in the marketing materials for the home. You see, it’s easy for a real estate agent to say “the building might need a total re-clad”, but what if all the floor joists are also rotted? If you see a leaky home/building for sale in the Mission Bay, St Heliers, Kohimarama area at just $270k, then surely you would have to be suspicious there is more than meets the eye, right? You bet! Especially when it’s on a tiny cross leased piece of land with no view.

So what’s it really worth?

Unless your an experienced builder or investor who has dealt with leaky buildings in the past, then in my opinion you will need a complete structural intergrity survey of the home first (Don’t get excited by the price to quickly)… and if it’s so rotted that it’s close to a ‘knock down’ (don’t forget to factor in costs to take it away), then it’s barely worth the piece of dirt it sits on.

Everything property is a good deal at the right price, but make sure you also factor in your building experience into the price… and don’t let the hype of an auction grab your bank account and tear it apart like I have just witnessed!

Maybe ask a current or past leaky building owner if they would buy another one for a cheap price.  I highly doubt it… especially if they aren’t experienced in the building industry. Take Care!