Overview

This document contains general recommended instructions for combining our windows and doors.

The following two terms are used in the context of combining doors and windows:

  • Mullion – used for the consecutive connection of two products with a vertical member.
  • Transom – placement of a product (usually a window) above another product (typically a door).

For each product there is additional detailed information on connection using mullions or transoms.

When combining two products it is preferable if they have the same frame depth, especially when connecting with mullions.

In order to combine products:

  • An I-shaped structural member or profile (I-mullion) is used for the vertical joining of the products.
  • A transom sill pan, or a combination of a transom sill pan and a structural tube, is used for the horizontal joining of products using a transom.

NOTE: In nail-fin type frames, it may be necessary to cut the fin on the spot at the location of the mullion or transom.

Why use mullions and transoms

The main reasons for using mullions and transoms are:

  • Increased structural performance.
  • Ability to combine multiple frames to cover large openings.
  • Ability to combine different product types (e.g. a sliding door with a fixed window).

Frame types and sill pan

Use block-type frames at locations where products are connected, e.g. at the sill. Factory-made I-mullions cannot be combined with nail-fin type frames.

A full-length sill pan is required for all products connected with mullions and a sill pan for all transoms.

Sill pans of custom dimensions can be supplied on request. Sizes greater than 4 m will be sent in segments. The joints shall be sealed at your own risk.

Mullion connection design parameters

When products are combined using mullions, the structural performance of such connection should be taken into account. The required strength of the connection of the I-mullion depends on the design category and the net dimensions of the frame.

For combinations that exceed the strength of our standard I-mullion connections, you are responsible for procuring sufficient structural elements to meet the design requirements.

I-mullions are designed to withstand wind loads greater than the lateral load. When connecting products using I-mullions, e.g. a hinged door next to a fixed window, you should take lateral loads into account. The hinged side of the door will create a lateral load on the I-mullion. The same applies when combining a sliding door with a fixed window. The lock side of the door (if the door is pulled while locked) will also create a lateral load.

NOTE:The use of structural members with thermal break products may affect energy performance (e.g. as regards ice, heat, vapor condensation etc.).

Transom connection design parameters

When using transoms, you should take into account structural performance both against wind loads as well as against bending. Screws are not used to connect the frames to the transom, since they damage the sill pan that blocks the passage of water between the products. The connection depends exclusively on the structural properties of the compatible sealant.

Deflection may occur when a window is placed above a sliding window or door. In sliding products there must be a clearance between the upper part of the frame and the sliding sash. . If deflection occurs in the upper part of the frame, it can decrease or eliminate the clearance, preventing the sash from sliding.

If the upper part of the frame of the sliding window or door is not supported, deflection from self-weight may occur. The problem is exacerbated when the additional weight of another window is placed on top.

For combinations that exceed the strength of our standard transom connections, you are responsible for procuring sufficient structural elements to meet the design requirements.

NOTE: The use of metal stack bars or other structural members with thermal break products may affect energy performance (e.g. as regards ice, heat, vapor condensation etc.).

Mullion installation instructions

These mullion installation instructions concern factory-supplied I-mullions.

  • An indent must be cut on the I-mullion on site so that it can pass through the fold of the sill pan.
  • Place the I-mullion between the frames as shown in the figure. Make sure that a bulb seal has been placed in the T slots of the I-mullion.
  • Fix the frame to the I-mullion using self-drilling screws.
    In GTF products you must remove at least the trims and possibly the glass pane, depending on its size, in order to fix the screws.
    The size and distance of the screws must comply with local regulations. You may also have to tighten the opposite screws to avoid loosening.
  • Apply a compatible sealant to all screw heads.
  • Replace the glass pane and trims (if required).
  • Apply sealant to the entire length of the external vertical joints, leaving a gap of 1.2 cm at the base for drainage purposes.
  • Place the support rod and cover with a compatible sealant to ensure that no water passes through the connected units.
  • Place an insulating sheet over the units, as shown in the figure, for additional protection against moisture.

NOTE: The insulating sheet is not provided by the factory.

Transom installation instructions

  • Apply a full layer of compatible sealant to the entire upper part of the lower frame, as shown in the figure.
  • Place the transom sill pan over the upper part of the lower frame.
  • Apply a compatible sealant along the entire length inside the fold of the transom sill pan.
  • Place the upper frame (transom) on the transom sill pan. Make sure that the base of the upper frame is pushed up against the inside leg of the transom sill pan and is in contact with the sealant.

NOTE:The use of metal stack bars or other structural members with thermal break products may affect energy performance (e.g. as regards ice, heat, vapor condensation etc.).