Monday, January 18, 2010

Inspection Number 8

OK, hang on readers the inspections are coming fast and furious now, well not quite a whirl wind of activity as of yet but trust me it all changes. There is really quite a trickle down effect as the agents get busy I have about a two to three week wait before I see the fruits of their labour.
Number 8 was a special inspection for me. It took place in Lindsay. I have a number of houses that are on my "homes that I really want to inspect" list. Now I know you are sitting there thinking, "this guy truly has no life", some days I wonder. Anyway, I am excited to tell you about this place, it was certainly on the list. Without question it was architecturally built, that being said it does have some odd lines to it, we will discuss these later.
The home is sided with wood shakes and field stone, two very nice earth products that really do complement each other. I am a very big fan of the wood shakes but find that there is a lot of misconception about them, and today I will take it upon myself to give you wood shake, 101, and 102. Ah yes you will be able to sit around the table at supper tonight, and when that awkward silence rears its ugly head you can chime in with confidence " So what do you think about those cedar shingles anyway" ( now you truly are an official house geek)
From an inspection stand point inspectors should always be trained to refer to the product as wood shingles / shakes. Being species specific can be a risky comment. One that you could be held accountable for should you mistaken one species for another. In Ontario, Alberta, and British Columbia I have come across four and maybe five different species. The most common of course is Western Red Cedar. It takes a well trained eye to be able to look at a cedar shingle and define it origin of species after it is a year or two old. In Canada we are blessed with two types of Cedar that are used in construction, that being the western reds and the eastern whites. Differences in there chemical make up is different but barely measurable. The resin that is with in the product make for a very water resistant material, as well as extractants that are toxic to decay fungi. These extractives actually will increase as the tree ages. It is important to understand that the Cedar tree is, as all trees are, made up of a number of layers. Starting at the core of the tree the terminology is as follows. First we have the Heart, this section of the Cedar tree is typical discarded as it is not all that stable or sound. Next on the list is the Heart wood, this is the money shot, this is the product that is sought after for shingles, shakes, and lumber and trim alike. The next layer is considered Sap wood, while this is a nice colour and makes for a nice contrast on lumber, it is a very week section of the product when milled. The "magic juice" that runs through the veins of this tree are called Polyphenole which is water soluble and Thujaplicans. ( throw that one out at the supper table and see the conversations that build off of it, oh ya). Another amazing property of Cedar material is the ability to insulate. The best of all the softwood species with an R value of 1.35 per inch is impressive. ( cellulose, a popular attic insulation in Ontario is 3.70 per inch) This superior insulation value ( as far as wood is concerned) can be contributed to the low density and presence of many tiny air spaces.
The home that I was looking at utilize a 24 inch long shake, sawn on one side. This is a premium product right down to the way it sawn. In the saw mills the ideal cut with this type of product is referred to as "Quarter sawing" this refers to the direction of the grain in the material. What the sawyer is looking to accomplish is a "radial grain" or straight grained shake. This is the product that absolutely should be used in a roof application due the fact that the shingle/ shake is much less susceptible to cupping or even longitudinal splitting. The shakes that are on this home are 100% radial grain, and was aging amazingly. At 38years of age no product defect was noted. This great product was complimented by the fact that the installers did not just fall off the wood pile, these guys new what they were doing, correct exposure, proper placement of fasteners, and an impressive staggering of joints, all of which to ensure a sound weather resistant exterior finish.
Terminology of wood shakes/ shingles seem to be all over the map as well. Here's the explanation.
A shake is split on two sides, literally that is what happens, this is not a saw cut it is physically split. This is one of the nice things of a wood that has been quarter sawn and has a very straight grain. It has the ability to be split with a metal throw and a sledge hammer. The irregularity of this product is certainly one of the attractions to this style of exterior finish. While I am a big fan of the shake ( split two sides) I do not like it for a roof application. The building code also views them as being a little more problematic , for this reason the application of shakes on a roof require a 36 inch course of 15lbs perforated tar paper ( and the new era product called "cedar breather" looks like a sheet of brillo cloth) at every course. If a home owner is determined to use shakes on the roof the product should be "split one side, sawn one side" this, at least makes for the shingle lay to be much tighter to the roof deck ( still needs the perforated tar paper and cedar breather ) The last of the styles is the sawn two sides wood shingle, they come in various dimensions.The width of wood shingles / shakes should not be less than 3 inches and not greater than 13 3/4 inches, the thickness of shingles does vary some what the standard butt thicknesses seem to be 3/8's, 1/2, and 5/8's for sawn shingles and typically about 3/4 inch for shakes. Wood shingles should not be shorter that 16 inches in length and are rarely longer than 24 inches. A premium "Certi. Sawn" 5/8's butt, 18 inch shingle is, in my opinion the best product for roof application.
I like the look that the White Cedar has as the patina ages out of the shingle. Whites age colouring are referred to as a silver black, while the reds age to a brown black colour.
The correct type of fasteners are critical to the longevity of a wood shingle. Steel and electrogalvanized fasteners will cause the "extractive bleeding" marks to form on the shingles. These take the form of blue black streaks that run down the shingle.
The other types of shingle that I have encountered are White Pine, Red Oak, Poplar, and Ash.
I have found that the type of materials used is generally what ever the most common species of tree is in the area. In Kentucky is where I came across the Oak shingles and then again in Bobcaygeon. This is the Cadillac of wood shingles with a projected life expectancy of 100 years where as cedar shingles (certi sawn 24in with 5/8's butt) are more in the 40 to 50 year area.

The field stone was the other impressive workmanship on this building, beautiful colouring, placement, and corner cuts. The challenge was the stone chimney and where it passes through the roof. flashing's at this point should be done by the mason in conjunction with the roofing company. This was not the case and the problems were evident ( inside leaking that had been repaired for the purpose of sale) the faint images of repair work on the ceiling were the telltale to suggest that this area was troublesome as was the caulking via slingshot all around the roof flashing. This repair represented a MAJOR concern in my report. (more that $500 to fix)
Architects are a curious bunch to me. The design work that I see time and time again that is not practical or in the houses best interest, are continually built, even though we all know ( those in the business) that they will be a point of failure. Case in point "brick corbeling" this is where we have a series of bricks at the top of the chimney where each course of brick extend beyond the course below it by an inch, which goes on for a number of course and then the course start to step back in. The negative results are that the water does not effectively drip off the chimney brick work. Instead, it runs down the brick. In turn the brick absorbs the water, it freezes and the ice expands and pops the face of the bricks off. this was the case on the second of the two chimneys that were on this house. A simple concrete pre-cast crown will eliminate this problem.

thanks for tagging along, certainly feel free to ask questions anytime, I extend the same courtesy to you guys as I do my clients .

PayPal - The safer, easier way to pay online!" type="image" border="0">

No comments:

Post a Comment