Seal Correctly - Product Guide for Sealing Windows and Doors

30 percent of all air leakage comes through windows and doors. With proper sealing, you can avoid air leakage and save both time and money on reduced energy consumption and maintenance. In this guide, you can read more about how to seal windows and doors in the best possible way. The guide is based on three different sealing methods and the products we recommend for optimal results.

Step 1 - Secondary Sealing

Always start with a secondary seal at the bottom of the installation opening (window/door opening) regardless of the chosen method. The function of the secondary seal ensures moisture protection against the frame in case of harmful water intrusion through windows and doors.

The secondary seal consists of the flexible and elastic sealing tape Flexseal-T that adheres to concrete, wood, steel, windproof fabric, or boards

Step 2 - Choose a method for sealing windows and doors

METHOD A - Expanding drive belt

EXPANDING DRIVE BELT T-EXPAND STANDARD OR T-EXPAND PRO

During new installation, the self-expanding drive band is mounted on the frame according to the product's installation instructions. The frame is placed in the opening in the correct position so that an even gap is created around with the chosen fixing/attachment. Be sure to check the swelling of the band according to the instructions and supplement with T-Fix adhesive and sealant if necessary, for example, if any corner has become unsatisfactory/leaky. Base the choice of the correct expansion range for the band on the gap measurement.

Materials needed:

Secondary sealing -Flexseal-T
Caulking/outside/inside -T-Expand Standard or T-Expand Pro
Accessories as needed -T-Fix

Advantages of Method A:

- Quick assembly
- 3 products in 1
- Weather protection during construction time (after full expansion)

METHOD B - Mineral wool caulking with diffusion-tight tape inside and diffusion-open tape outside

MINERAL WOOL SEALING WITH EXTERNAL AIRTIGHT-T

Sealing is performed in the gap between the frame and the opening around the installed window or door. The sealing should not fill the gap all the way to the outside of the frame. A distance or gap to the outside of about 5-10 mm is recommended. This ventilating gap has a pressure equalizing ability and evacuates any water that may have formed inside more effectively!

OUTSIDE

The exterior of the frame over the sealing gap towards the opening/frame is taped with the diffusion-open and weather-resistant tape Airtight-T according to instructions. The tape increases the drying ability of any internal moisture. For wind protection fabric, Airtight-T 60 mm is recommended, and for wind protection board, 75 mm.

INSIDE

Internally, the sealing gap is taped completely and airtight, between the frame and reveal, with T-Flex tape (60 mm with slit). Ensure that the taping on the frame is covered with trim strips in the usage stage (no visible tape afterward).

Materials needed:

Secondary sealing -Flexseal-T
Caulking - Suitable mineral wool caulking
Outside -Airtight-T
Inside - T-Flex

Advantages of Method B:

- Traditional method
- Diffusion-open exterior that allows drying
- Weather protection during construction

METHOD C - Mineral wool caulking with diffusion-tight tape inside and outside

MINERAL WOOL SEALING WITH EXTERNAL T-FLEX-OUTDOOR

OUTSIDE

The exterior of the frame over the sealing gap towards the opening/frame is taped with the completely airtight and weather-resistant tape T-Flex-Outdoor all around except for the slot opening at the bottom which should be completely open. Consider the construction exposure time for this method. For longer construction periods, method A or B is recommended. For wind protection fabric, T-Flex Outdoor 60 mm is recommended, and for wind protection board, 75 mm.

INSIDE

Internally, the sealing gap is completely taped, between the frame and the reveal, with T-Flex tape (60 mm with slit). Be careful to ensure that the taping on the frame is covered with trim strips in the usage stage (no visible tape afterwards)

Materials needed:

Secondary sealing - Flexseal-T
Caulking - Suitable mineral wool caulking
Outside - T-Flex Outdoor
Inside - T-Flex

Advantages of Method C:

- Traditional and simple method
- Low material cost

How much material is needed?

In our calculation tool, you can easily calculate how much material is needed for the different methods.

To the calculation tool

Products for sealing windows and doors

T-FLEX

Our 60 mm T-Flex with slit is specially designed to seal window gaps on the inside. In combination with Airtight-T, it provides excellent moisture protection and a tight climate shell.

- Very good adhesive ability
- Age-resistant for at least 50 years
- Wide range of applications, tested at RISE on many different surfaces

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T-FLEX OUTDOOR

T-Flex Outdoor is a diffusion-tight and flexible exterior construction tape with optimized properties for protection against sunlight (UV), high adhesive strength, and long durability.

- Optimal for outdoor use
- UV-protected for up to 12 months
- Good adhesion on difficult surfaces
- Age-resistant for at least 50 years

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FLEXSEAL-T

Elastic, flexible, and weatherproof sealing tape, primarily for external use behind facades and roofs.

Excellent as a secondary seal in window and door openings where a robust, water-resistant, and formable sealing tape is required at the base. Adheres excellently to most surfaces (such as concrete, wood, steel, windproof fabric, and exterior board).

- Flexible and elastic, retains its shape after stretching
- Split protective film which is optimal for taping in corners
- Adhesive that works in low temperatures

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AIRTIGHT-T

Airtight-T is a unique high-performance fully diffusion-open functional tape primarily for external use. Its primary use is for joints and penetrations in the climate screen where moisture protection and weather-resistant properties are required, especially during construction. Excellent for sensitive and complex construction details such as window and door connections. Against windproof layers where both moisture protection and openness are required for the best possible drying of construction moisture/steam from within. A permanent seal and durability for the construction period and the upcoming longer usage period.
As weather protection (including UV protection) during the construction period for up to 3 months (unprotected exposure). Thereafter, built-in protection by the permanent surface layer and against air gaps.

- Adhesive that works in low temperatures
- Split protective film that simplifies installation
- Attaches to wind protection board
- Adheres to concrete and plaster surfaces

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T-EXPAND STANDARD

T-Expand Standard is an expanding sealing tape with a barrier membrane, primarily intended for jointing and sealing during the installation of windows and doors in insulated constructions. It provides the joint with a diffusion-resistant interior, a diffusion-open exterior, a waterproof exterior, absolute airtightness, good thermal insulation capability, and sound insulation.

The installation is carried out according to instructions around the frame of the window/door, the product is self-adhesive. After fixing the frame in the section, wall, or ceiling, the sealing tape self-expands, so that the joint is sealed and tightened.

- High sound insulation and good thermal insulation
- Simple one-step installation, no sealing tape required
- Expansion time at least 0.5-3 h
- Cost-saving as the product reduces the building's energy needs

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T-EXPAND PRO

T-Expand Pro is used for sealing and caulking during the installation of windows and doors, primarily in insulated structures. It provides the joint with a vapor-tight interior, vapor-permeable exterior, waterproof exterior, absolute airtightness, good thermal insulation capability, and soundproofing.

- High sound insulation and good thermal insulation
- Thin unexpanded with easy one-step installation, no sealing tape required
- Expansion time at least 0.5-3 h
- Cost-saving as the product reduces the building's energy needs

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T-FIX

Elastic adhesive and sealant made of black hybrid polymer for water and airtight joints, connections, or seams. For external or internal use.

- High adhesion on many surfaces
- Weather-resistant (UV and water)
- Solvent-free and low emissions
- Aging resistant

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Do you have questions?

Our sales representatives are available to answer questions about our products, the different methods, or anything related to sealing windows and doors.

You can reach advisory sales representatives for your region here