Apartment Troi - Simple window (sash/casement//sliding) - Low Impact (no impact or minor impact from both inside and outside) - Uw 1.05 W/m²K

The Building

Building post-intervention

Railway worker house

This apartment is part of a residential building in Bolzano, in the north of Italy. As many others, it was built in the 1920' to home the large number of railway workers who came to Bolzano at that time.

More Details

The Solution

Solution post-intervention

Solution post-intervention: Bolzano_solution_apres_3.png

Solution post-intervention: Bolzano_solution_apres_4.png

What is the Solution?

The solution consists is replacing glasses of both windows of the box-type window wile restoring the sashes. The glass of the outer window was replaced with laminated safety glass and the one of the inner with insulating double-glazing.

Why Does it work?

Even if the building is not listed, it was decided to keep the original frames of the upper apartment. They were warped and needed to be restored. The outer window is round-arched and has cross bars and the inner window has a nice overlapping closing system. The two windows had single glasses, so it was first necessary to mill wider the sash to insert the new glasses. A sealant was also installed between the sash and the frame of the inner window.

PROS

Preservation of the historic window frames, including profiles and proportions
Improvement of energy performance.
Improvement of airtightness.

CONS

Replacement of historic glasses

Window Type before retrofit

Box Type Window

Window glass type

Inner window: modern double glass. Outer window: laminated glass

Window frame material

Wood

Window position

In the middle

Shading

Historic shutters were maintained.

Health issue

There is no real health issue in this case for the carpenters. The only risk is the rise of the moisture load, that can be easily controlled by opening windows or installing mechanical ventilation.

Technical drawings

Installation Method

The windows were remove from the wall and restored on site by carpenters.

Moisture Management and Technical Compatibility

Moisture management has not been addressed in this restoration. Therefore, when the glass is replaced, less moisture will be able to condense on it, resulting in a higher moisture load in the room. This can be compensated for by installing mechanical ventilation to reduce the load. Another problem is the transfer of moisture in the box of this box-type window. However, as no sealant has been installed in the outer window, the moisture will be able to escape easily.

Airtightness

The airtightness was first improved by restoring the warped sashes. This led to normal use of this historic window. A sealant was then applied between the sash and the frame of the inner window, resulting in airtightness similar to a new window.