Our wooden 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.


 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.

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.


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.  In addition all of our installations come with

Fensa certification and an insurance backed guarantee. 

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.

If you are considering replacing your existing windows with timber box sash or casement windows please take a look at our website for inspiration I Foster & Sons