An installation service is available via our network of trusted Approved Installers. Each Installer is put through an installation training programme that ensures we obtain the best services available.

Dealing with projects ranging from a full Self build home to a garden extension to replacing your windows and doors we are here to help.

Alex Forsyth Ltd
Units Q R Burnhouse industrial Estate
Whitburn, Bathgate EH47 0LQ
Tel: 01501 745149
Contact: Douglas Forsyth 07803 967401

BK Joinery Ltd
Aonach Mor
Wrae, Turriff AB53 4NX
Contact: Brian Killoh 07900 251127


Gallabog Croft
Balgaventy Rothienorman
inveruire, Aberdeenshire AB51 8XX
Tel: 01464 871371
Contact: James Hall 07764 478487


What Our Client Says

"Smooth sailing with the experts, Alex Forsyth Ltd was recommended to us for installation as we were taking on the extension ourselves and were very nervous about specifying and sizing. Doug Forsyth however, was a god send. He came to site a few times and assisted with measuring up. He actually uncovered some minor issues that we hadn’t noticed, but Doug produced solutions to these issues, which were not part of his remit, a great service and wouldn’t hesitate to recommend!”

Kristian Clezy, Larbert

"Alex Forsyth Ltd were brilliant, Doug measured up then took us through all the style and colour options. We were looking for a finish that would complement the building, Doug suggested Anthracite Grey which works perfectly! The guys couldn’t do enough for us, always on hand to answer any questions and the finish on the building is very high quality. In fact we loved the windows and the service so much that we decided to replace the rest of the windows & doors in the property within the year! A pleasure to deal with, I would happily recommend to friends & family. We even had a stranger put a card through the door to ask for details of supplier and fitter!”

Diana & Jamie Mclean, Ash Dean, Crossford


Installation Guides

We recommend using an approved Installer as they are specially trained in installing VELFAC/Rationel windows. VELFAC & Rationel product ranges are innovative and advanced window systems which are suitable for the Scottish market. It is not mandatory to use an Approved Installer but we do strongly suggest that if not going down this route then the installation guides and short video link below are carefully reviewed at order sign off stage to ensure familiarisation with the process.



Click on logo to download guide


Interface Details

The build sequence needs to be considered when using render or cladding externally, the external finishing’s should be applied to reveals BEFORE window installation takes place. The weather-seal tape must be fitted to the finished external structure and in front of the cavity.

Please find typical interface details in PDF below,

If the detail you are looking for is not here or if you would like in DWG format please contact us

Recommended Installation materials

purchase via


Supplied with Windows & Doors
Spares can be purchased via