Today we started dismantling the interior of the first floor of ``Hatsu no Ie III''. The order of destruction is from top to bottom, that is, proceed from the ceiling. This house was a one-story building when it was completed in 1981, and until the second floor was added eight years later in 1989, the attic on the first floor was an attic...for that reason, when the ceiling was removed, it was completely filled with stuff. Glass wool (ceiling insulation for a one-story house) was exposed. For the ceiling, another layer of gypsum board was added on top of the original decorative gypsum board when the construction was completed, and the attic was connected to the underfloor to prevent rat droppings. If we just laid it down, air would run through the gaps in the veranda, and we visually confirmed that the glass wool would become black due to the moisture in the room, causing dusting and other problems.
竣工時の天井用化粧石膏ボードの上にもう一層石膏ボードを増し張りしてクロス張としていた。
On top of the decorative gypsum board for the ceiling at the time of completion, another layer of gypsum board was added to create a cross-covering.
This cut shows that insulation must be installed without any gaps in both walls and ceilings. The dust that looks black is actually a trace of humid air passing through. If air moves through the glass wool, insulation will not work.
The ceiling finish on the first floor has been removed. If you simply lay glass wool like a futon over the field edge, the humid air inside the room will run through the gap between the field edge and the glass wool, leaving a black mark called dusting. Even though the same ceiling is insulated, it is easy to understand why it has evolved into sparge insulation. Naturally, carpenters engaged in demolition are fully protected with dust masks, goggles, and gloves. At that time, glass wool was prickly and difficult to touch with bare hands.
Rat droppings were found in various parts of the building, indicating that the floor joist flooring, floors, and attic were continuous passageways for rats.
Construction began on May 11th (Thursday) for performance improvement renovations (long-term high-quality housing renovation promotion project) ``Cold House III'' (Hassam Noie III). The first application for confirmation was made in 1981 (New Earthquake Resistance), and the second application was made in 1989 for the purpose of adding a second floor from a one-story building. A 42-year-old wooden mortar two-story building will be completely renovated to improve its performance. Today is the first site meeting after Hiei Construction and the owner moved out. My job is to have the carpenter partially dismantle the floor and walls and check the actual situation. The reason is simple: confirmation drawings from this era are often unreliable, and non-destructive and visual inspection is the limit of investigation while the homeowner is present. The results of the inspection were that the exterior mortar was 20mm thick instead of the 30-35mm thickness that was common at the time, the underlying loose boards were 12mm thick instead of 18mm, and the interior board was 9mm thick, so the horizontal rim was constructed at @455, and the first floor joists are 45 x 105 (mm), so the pitch is @1820. We will take into account what we learned today and make corrections to the implementation drawings.
木造モルタル２階建て（元々は平屋）築42年をマルっと性能向上改修します。
The 42-year-old two-story wooden mortar building (originally a one-story building) has been completely renovated to improve its performance.
Looking up at the flat roof from inside. While roofs in Honshu slope toward the outside of the building, flat roofs in Hokkaido have the opposite slope. Surprisingly, the construction is similar, with @455 having □45 rafters compared to the main building @900, followed by 12mm roofing boards, roofing, and colored iron plates, in that order. What you'll see is the black condensation marks left by moisture escaping from inside the room and coming into contact with the roof boards, which have been cooled by the snow on the roof.
Evidence shows that the bathtub was an FE type (a type that uses indoor air for combustion) when it was first built. To prevent incomplete combustion of the bath kettle, we had to draw in outside air at below zero temperatures. It is easy to see why it evolved to the currently common FF type (in which outside air is introduced directly into the combustion section for combustion).
The glass wool on the indoor side is relatively clean. On the other hand, the outdoor side is black. The reason is simple...the vinyl cloth on the interior actually acts as a moisture-proof sheet and prevents moisture from entering the walls. Studs are 30 x 105 (mm) @455, braces are 45 x 90 (mm). The black waterproof paper (asphalt feld 17kg/m3) is visible through the gap between the 12mm loose boards on the mortar base.
This is the outdoor side of the glass wool, which was so clean indoors with no humidity. From the indoor side: glass wool, loose board 12mm, waterproof paper 17kg/m3, lath mortar 20mm
This is the middle partition. At that time, the mainstream interior board was a thin 9mm, so the horizontal rim 18 x 45 (mm) @ 455 was standard for reinforcement. What is surprising is that the markings on the pillars and studs were done on-site. Each one is dug out with a saw and chisel. Nowadays, this job is all pre-cut router processing. A young carpenter who only builds new buildings can't do it (lol)
Open the tatami floor and check the structure of the floor. Under the tatami mats, there was a control panel (lauan plywood) rather than a wooden board.
100mm glass wool made 40 years ago (the joist height is 105mm) which is dangerous to touch with bare hands. Trical net between the joists to prevent falls.
Opening the tatami floor. Even if the glass wool is 100mm thick, exposing raw glass wool directly to the cold air under the floor will not work very well. If the floor is covered with a breathable tarpaulin sheet instead of Trical Net, the floor insulation will be effective. I can only say this now...
Under the floor without a moisture-proof sheet. There is also a slight musty smell. The forked tube visible under the trical net is a kerosene oil line (copper pipe). Moisture-proofing and insulating the subfloor surface will double the capacity...
