Triple Glazed Lead Lights
Traditional Casement Windows
Traditional box Sash Window
Casement windows
Black and white casement window
Box sash windows
White wood box sash window
Entrance doors
Wooden blue front door
Bifold doors
Wood Bi-fold doors
Coloured fanlights
Coloured glass fanlights

Wooden Box Sash Windows

Vertical Sliding Box Sash Windows

Our timber box sash windows are custom made in our own workshop by our highly skilled team of carpenters. We offer our customers a full replacement service which includes new boxes, architraves and nosing.  All our box sash windows are fully draught excluded and operate on a spiral balance system. We pride ourselves in our attention to detail so are happy to copy your original horn feature and arch top, alternatively we are able to produce a new design for you.  Should you require glazing bars then we manufacture a 32mm bar which can accommodate a double glazed sealed unit.

Glass options

 We have an extensive range of glass options for you to choose from which includes, clear, various obscure patterns, coloured, toughened, acoustic sound deadening and laminated glass.  Safety is of paramount importance to us, therefore all our low level and bathroom windows are fitted with toughened glass as standard.

 In addition our sealed units are all double glazed with softcoat low emissive glass, a warm edge spacer bar and are argon gas filled.

Window Security

At I Foster & Sons we understand how important security is for our customers and are proud to confirm that all our box sash windows are fitted with key operated twist locks, dual position restrictor bolts, D handles and finger lifts which are available in a variety of colours and finishes.

Finishing and Paint

We finish our box sash windows with three coats of microporous paint or wood stain, alternatively we can source a brand or colour of your choice.

Window Restoration

Our passion is restoring houses back to their former glory, therefore we specialise in re-opening box cavities and removing plastic or aluminium windows.  We are also able to replace stone cills and re-build bays.

Whatever your requirements we are always happy to discuss your plans and ideas and offer a free no obligation quotation.

Fensa Registered Company
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I Foster and Son Established 1987
White wood box sash windows
Grey Wood Box Sash Windows
White Bay Box Sash Window
Traditional timber white box sash windows

Visit our Showroom

To see examples of all our timber windows, doors and box sash windows


I. Foster & Sons Limited
Spring Gardens Industrial Estate
Romford, Essex, RM7 9LD

Opening times

Monday to Thursday 8am to 5pm.
Friday 8am to 4pm
Saturday and evenings by appointment.


TEL: 01708 725325
TEL: 01708 728901
MOB: 07831 259156
EMAIL: [email protected]