What Is It? And Why Did A Chippie Make It?
Well first you might ask is ‘What’s a chippie?’ Well that’s simply an old term for a carpenter or wood fitter, because they were very effective in removing large amounts of wood with adzes, axes and chisels.
This is of course in the days before power tools and literally ‘the chips were flyin’. A good tradesman kept his tools sharp so when notches or long rip cuts were required they reached for the blades first. In skilled hands this was faster than the alternative and very accurate.
That’s the chippie, but what is this and why is it different? This looks similar to but not the same as what is built today. The shape tells us its the interior of an attic gable end wall, but they aren’t built like this anymore.
This photo shows a 50s build, near the end of an era for this type of construction which was used for hundreds of years. You can’t see it in this photo but the wall ‘boards’ are 3″ thick. They are the wall. There are no studs!
Yes 3″ thick!
This is not the platform, western, or balloon framing known to the current generation of carpenters and builders. There are no studs here!
This is more closely related to log cabin technology than anything else. It isn’t fitted with corner notching the way logs were (modern nails are used) and the ‘logs’ have become squared timber planks. (The camera flash makes them look dressed but they are actually rough sawn.)
The french called this method ‘pièce sur pièce’ (piece over piece) and it a compression technology that structurally transmits weight the same way stone and masonry structures do.
Some pieces were “keyed in” with birds mouth notch joints like this photo;
Note the small nails relative to the timber size. This is toe nailing. Its function is just really to hold it in place. The fitting, notching and weight are what do the work in holding the wall together.
Doors and windows have to be preplanned to fit under the bays formed by theses notched beams. You can’t just cut holes in these walls and frame a door or window opening. There is no ‘point loading’. All pieces cary weight
Floor framing is not a built platform as it is done now. Rather individual joists are ‘let in’ notched into the exterior walls a seen below;
Typically the vertical pieces had grooves in their sides that the horizontal pieces were notched into (similar to a mortise and tenon joint). Positioning and spans were a product of the size of the materials avaliable.
Exterior walls were commonly faced with brick, while inside faces were furred out and plastered.
Both faces of the wood were protected with tar paper. The exterior was done to protect the wood from the drainage plane behind the masonry (typically a one inch air space.. The inside was similarly protected against the huge volume of water temporarily introduced to the building by the plastering process. It often took up to three months to dry out.
Interestingly, although there is no insulation product installed here, the whole wall assembly is rated at nearly R20. Not bad for ‘no insulation’!
This construction can be found in most city cores in brownstones and masonry clad structures. Like the first photo they are also found in 50s build suburban housing divisions. It was a good solid building method.
It does have some drawbacks. Compared to current construction it uses a massive amount of wood and quality was hugely dependent upon the builders experience and knowledge as well as the tradesman’s skills.
Structurally it is sound but it does not lend itself to easy renovation. Any changes require an engineers consultation and an experienced crew.
As an inspector I field calls with people asking if I have experience with certain areas of the city. What they are really asking is if I understand how those homes are built and will I be able to recognize thier particular problems and know it they have been correctly renovated in the past.
And thats a fair question. Thats the service needed for homes built this way.
Original blog post on ActiveRain: Link to Blog Post