Bay Window Specifications
Bay windows are windows made up of a combination of windows from our ranges. These are typically used using a larger front window such as 1200mm or greater and two returns which are generally single module width windows hence 630mm or 488mm.
- Splay or square bays can be supplied and factory assembled with mitred cills.
- Square bays are supplied with 68mm x 68mm corner posts as standard.
- Splay bays are supplied as standard at 45 degrees. Other angles are available upon request.
To determine window sizes required for your bay window we require the brickwork dimensions as shown in the figures below:
Fig 1: Bay permutations with dimensions required
Corner posts and fillets are supplied to fit the window frame used. Window cills are extended and mitered to suit.
Bay windows - Installation Part L
Whether square or splay, bay windows require careful consideration for installation. Part L of the Building Regulations states that thermal performance around openings is achieved. Previous methods were to butt corner posts, fillets or jambs to the corner of the brickwork or to use a birds mouth detail to sit into the corner. These can create a cold bridge at the joint and are unacceptable in the current regulations. We recommend two methods as follows which should allow compliance:
- Recommended Detail (1)
The brickwork is angled and bought up to the edge of the window jamb thus joining flush and giving a pleasing aesthetic finish.
- Recommended Detail (2)
By adding an angled fillet to the internal of the jamb to meet to brickwork. In theory this is easier to achieve however may not gain the aesthetics of the Detail (1).
Bay Window Cills
In order to comply to the requirements of "Robust Detail" a 30mm overhang must be achieved from the window frame over the cavity.