Exclusive deep 55 mm cill

Wednesday, May 16th , 2018


The exclusive deep 55 mm GRP cill available as an optional extra on the Vintage Traditional sash window is a beautiful feature designed to achieve the authentic appearance of an original 3” timber, perfect for use in a Conservation Area. 

Ray Rabett, Technical Director says “The most common request from customers about product improvement was “we need a deeper cill to mimic the old ex 3” timber cill” Masterframe has responded and this cill is now rolling off our production line.

Design was quite complex, requiring 12 revisions to get the cill perfect. The design criteria was that the cill had not only to replicate the old timber cill, but critically could not undermine the WER (BFRC window rating scheme), it had to remain an A rated product.  The intention was to also improve the weather performance if at all possible.  The final design has maintained a WER rating of “A” +1 result (to be ratified) and increased the weather performance to 250pa.

The increased strength brings a further advantage; the most common installation issue we get called to look at is where the cill has bowed upwards and the sashes are not closing properly.  This occurs because the installer has not packed underneath the jambs as they should. This new rigid GRP cill will overcome this problem, even if the installer does not pack the frame correctly. The strength of this new cill is 12.289 n/mm2 which compared to the reinforced standard cill at 0.769 n/mm2  is stronger by a magnitude of 16.8 times. “

The strength of the deep cill has another advantage, allowing larger and more unusual windows to be replicated more authentically, for instance where required in sea front hotels, renovated / converted former schools, industrial buildings and ecclesiastical buildings.

The deep cill is indistinguishable from the other PVC-U sections because all are bond wrapped in the same Renolit foil to maintain the appearance of timber.

Watch our video to find out more about the other features offered on the Vintage Traditional sash window and download the brochure here.




Learn why you get better windows because of these

  • BBA logo
  • ISO logo grey
  • Secured by design logo grey
  • BFRC logo grey
  • Energy Trust logo Grey
<h3>Setting standards, safeguarding interests</h3>
<p>Masterframe have been GGF members since the mid 90s. Our MD has served on the GGF main board and chaired the Home Improvement Executive, FENSA and the BFRC. Membership gives you greater protection on a number of levels.</p>
  • DGC logo grey
  • CE logo grey
How can we help you?

Enter your details and we will contact you to discuss your requirements further