Sliders Bi fold door issues

12 May 2018
Reaction score
United Kingdom
Hi all

Please can you help me with some issues we have with some Sliders Evo Ultimate aluminium bi fold doors.

Two external sets were fitted by our builder on a single storey extension and when it rains they leak a lot!

The company who supplied them to our builder has been out and just fobbed us off. (Polar Windows Chesterfield)

We are trying to understand how they should dispel rain water so we know if they have between them bodged them up and we are storing problems for the future.

There’s a track on the low profile threshold which was filling with water which drains from the bottom of the doors into the track when the doors are shut.
It was also draining into the house and cavity because the builder hadn’t put the cill end caps on properly (he did them after fitting)
He’s since come back and pumped tubes of Stixall / ct1 Into the side of the cill to seal it where the end caps should have been.
The water is now draining from the track (via holes drilled by our builder that he initially put screws into ) and down into the cill and then out of the front the cill via the proper drainage.
However we note that any amount of water onto the window results in it going between the rubber gasket and glass into the door itself and into the track. This track has filled and water entered the house too so we are very worried about the inevitable wet weather we are likely to get in the future.

The supplier Polar says this drainage process is all perfectly normal and part of the design.
Sliders will not discuss their product with us at all as we are not their customer. They are actually very rude!

Have attached some pics to help explain the issues.

Does this all sound ok or not?
What should we do?

Thanks so much


  • 7636D749-43E6-4ACB-8505-78402E0C1419.jpeg
    186.9 KB · Views: 233
  • 7C8D9662-AAE6-434E-9EC8-00AB4EE0580C.jpeg
    237 KB · Views: 234
  • E72C7697-A5EE-4D35-981D-1423D15FF75B.jpeg
    166.3 KB · Views: 240
Sponsored Links


15 Apr 2006
Reaction score
United Kingdom
Well as i have never fitted this product i cannot be sure i am correct but most aluminium systems would be pretty similar.
You need to fill the ends of the cills with a load of silicone on most systems as the drainage runs out of the bottom of the cill not like upvc that runs out on top of the cill. So fill the ends of the cill then put end caps on. if you do not do this any water that enters the drainage in the cill will run to the ends of the cill causing damp at each end.
27 Apr 2011
Reaction score
United Kingdom
As God says.
Fitted by a builder rather than a window fitter is the main problem. As well as not having sealed the ends of the cill it is common that they haven't sealed the frame down onto the cill correctly.
Impossible to tell without taking the frame out and refitting it.

Also most bifold manufacturers state in the small print somewhere that the low aluminum thresholds are not weather rated. Hard to tell from your pics but I think your external ground level is low enough that this is not the issue you are having though.

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Sponsored Links