Stone House Reno: 2. Parging and Window Frames
April 13, 2009
By the time I’d figured out how to do it, the job was done.
The interior walls of the old stone house needed a lot of work because the wind could whip right through in most areas. I bought a used cement mixer, a trailer-load of masonry sand, a few types of cement, and learned how to make parging mix. My dad’s recipe didn’t warn me that the ingredients would form into a ball and just roll around in the mixer unless I took care in the way I mixed them, but eventually I figured it out. (See Chapter 6 of this series for more detail).
Then came the problem of getting the stuff to stick to the dry stone and lime mortar of the wall. The first few days produced little success, but gradually I learned to make the mix stickier than the mud used for blocks and bricks, and to work my way up the wall, packing the cracks full directly from the surface of the hod (flat tray to hold the mortar) with a small trowel as I went.
As the mix improved, even Mom got into the act, chipping in on what I came to call her ceramics project. Filling the gaps between timbers above the windows defied physics and I eventually resorted to foam, but the worst part of the wall-repair project was the seven-foot stretch where the hearth had been torn out after the fire. No one bothered to make any repairs; they just studded and plastered over the blackened hole. This left a thin, fragile wall with lots of holes through to the outside for mice, bees and winter breezes, so it had to be reinforced.
Never having built a stone wall before, and confident that this one would never be seen once the sheetrock was on, I decided to buy 6″ chunks of limestone from a local quarry and have at it. Progress was slow and of indifferent quality. Then we tried laying an outer row of old bricks, and tossing rubble and mortar into the gap. This was effective, but made grave inroads into the brick supply around the property. The only part of the process which worked well was mortar production, so we finally set up permanent forms out of ¼” plywood and shoveled the cavity full of mortar and small stones. This proved relatively quick and airtight, though it was still hard to get the mix into the top 6″ of wall with a beam in the way.
It seemed logical to replace the window frames while the masonry equipment was still out. When disassembling the window panels I had been impressed with the 17″ fir boards the original builders had used to span the exposed stone between the windows and the plaster walls inside. It turned out that they had used fir as well for the actual window frames. They dovetailed together 3 X 6 inch planks for the vertical box which pushed against the stone and held the two sections of the window.
Without a supply of dry 3″ material, I had to glue up blanks from pine and treat them with preservative. This was time consuming but not difficult. I opted for long screws rather than dovetails, rationalizing that my frames were restrained on all sides by the stone walls, whereas the originals were likely used as a guide for the masons. Besides, if those old guys had had 6″ Robertson screws and a cordless drill, I’m sure they would have used them.
Perhaps the most perplexing math problem I faced on the whole renovation was preparing the thermal pane order for Healey’s Glass. Where was Mrs. Dowsett, my grade 13 algebra teacher, when I needed her?
A single window would be easy: just measure the size of the cavity, then subtract however much of the stiles and rails is left after the grooves are cut in the wood to hold the window. Subtract another 1/16 on each side for miscellaneous, 1/8 in height for the little rubber pads to support the thermal pane, and you have it.
But the windows overlap. That means two layers of window and frame at the middle of the cavity. At the planning stage, who knows how (or even whether) the thermal panes meet? What’s more, the inside window is higher up the sill, which sits on an eight degree angle. And these thermal windows are expensive, so mistakes are not in the budget. Yikes!
I put in many hours on the computer over this one, and I’m still not quite sure how they all fitted, but they did. Seems to me some of the dadoes were a bit deep, but the frames have held together for four years so far and the weather stays outside, so I can’t complain.
Without a good shaper at the time of the window construction, I used a dado head on my radial arm saw to make the grooves for the thermal panes in the sash. I still remember counting my fingers a lot that winter. A radial arm saw will do a lot of wood shaping operations (all of them dangerously) but a blind dado for a 3/4″ window is a scary operation, indeed.
When an old Poitras shaper arrived, and later a power feeder for it, my fingers positively wept with relief.
For other articles in this series check:
https://rodcroskery.wordpress.com/category/renovating-a-stone-house/
the Walnut Diary 