Trikåfabriken

The Building

Building pre-intervention

Building pre-intervention: Malmo_Batiment_avant_03.png

Building pre-intervention: Malmo_Solution_avant_01.png

Building pre-intervention: Malmo_Solution_avant_02.png

Building post-intervention

This knitwear factory was built in early 20th century in Malmö. Knitted underwear for ladies was made there. It has been converted into a sustainable office building in 2022.

More Details

The Solution

Solution post-intervention

Solution post-intervention: IMG_5090.jpg

Solution post-intervention: IMG_5092.jpg

What is the Solution?

The solution consists in replacing the two windows of the box-type window with double glass and to add an automated sunscreen between them.

Why Does it work?

The building is not listed, but it is subject to the chapter 8 of the Swedish Planning and Building Act (2010). This act mentions that "A building that is particularly valuable from a historical, cultural-historical, environmental or artistic point of view may not be defaced.". New windows with insulating glass have been recreated in the old style.

PROS

New windows must be designed as copies of original windows in terms of material, shape (arched or rectangular top), timber dimensions, dividers, hanging, drip mouldings and other details.
Improvement of energy performance.
Improvement of airtightness.
Control of solar gain while preserving the heritage significance of the window.

CONS

Replacement of historic windows
Automated sunscreen need maintenance

Window Type before retrofit

Box Type Window

Window glass type

Modern double glass

Window frame material

Wood

Window position

Inside

Shading

Windows in sunny locations have been fitted with an intermediate sunscreen that is controlled by sunlight and temperature. The building has been divided into different sections where each section is controlled by a sensor placed on the roof. It reacts to the sun and follows a sun curve. When the sun is shining, the curtains close automatically, and they open automatically when the sun is no longer there. However, with a certain delay (sun curve) to minimise the curtains going up and down as soon as the sun goes into clouds. The curtains can be temporarily controlled at each window, but after a couple of hours they automatically go into the position indicated by the sensor, in order to minimise the need for cooling on sunny days.

Health issue

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

Technical drawings

Additional documentation

Installation Method

New windows with insulating glass have been recreated in the old style.

Moisture Management and Technical Compatibility

Moisture management has not been addressed in this restoration. Therefore, when the whole window 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 new box-type window. Airtightness is assumed to be very good, so air (and thus, moisture) can be stuck between the two windows if no air intake is planned.

Airtightness

The airtightness was drastically improved by replacing the two windows.

Before retrofit

After retrofit

Before retrofit

Uw-Value

2.5

After retrofit

Uw-Value

1.1

Before retrofit

Ug-Value

information not available

After retrofit

Ug-Value

information not available

Before retrofit

g-Solar factor

information not available

After retrofit

g-Solar factor

information not available

Assessment

Window type

Simple window (sash/casement/sliding)

Frame material

Timber

Aesthetic impact

Low Impact (no impact or minor impact from both inside and outside)

Frame improvement

Yes

Glazing improvement

Yes

Additional glazing

Yes

Airtightness improvement

Yes

Window U-value

1 < U <= 2

Shading

Yes - reuse existing appurtenances

Circular approach

Yes

Circular approach (Additional info)

Repairing the frame instead of replacing. Most of the existing windows have been refurbished, with only a few replaced by replicas due to their poor condition. The existing windows were upgraded by replacing the original single glazing with thin, krypton-filled double glazing and adding seals to ensure airtightness.

Investment cost

Medium Low