Sash Window Restoration

Sussex Sash window Restoration Ltd is the only company that can restore your sash windows using the same method in which they were made originally.

we only use traditional methods to re-construct the sash windows to how they were first made.
We come across many windows that people have tried to restore. Some things that some carpenters or companies have done or used to try and restore the sash windows is shocking, and can cause you serious problems in the long run. S A big thing we encounter is foreign objects in the windows, the culprit being screws and nails. Whether this is in the sash window or the box frame it causes ROT, no question about this.
When windows are constructed they don’t use screws or nails they use wood on wood the only exception should be when you’re extending the window cills, when half has rotten away. This should always be doweled to create the seal around the screw and not filler because the dowel also moves and shrinks at the same rate as the wood you have installed with the timber being the same timber as you have used before.

This is how we restore sash window restoration

First We will take off all the paint to see how far the rot has gone for the reason stated above. Someone could have put nails/screws in the timber, it could have a lot of two-pack filler in areas where rot or water has attacked the windows from failing puttys, flaking paint and the joints opening up but these are only a few examples.

The rot usually forms around where you have had lying water or water ingress these points are usually at the:

  1. bottom of the stiles were you have the end grain of the timber touching the sill this is the point of the timber that will let in most water and acts like a sponge
  2. The bottom bar were lying water sits on the window sill or the puttys have failed
  3. The meeting rail this is where condensation has formed on the inside, water ingress from the puttys. This can travel all the way through the wood to the screws on the sash window furniture and with the window glass being upgraded this can cause a serious weakness in the wood

When most decorators paint sash windows they only scrape the paint and the timber out and two-pack the affected areas that are hiding the problem. Wet rot is a fungus called ‘Coniophora Puteana’ or commonly known as ‘Cellar Fungus’. So all your painters are doing is helping the rot to spread and attack the internal part of the timber because it certainly can’t rot the two-pack filler. A main reason they do this is cost and time. Dry flex costs £45 per tube and if you are not trained or haven’t used this product a lot than this can be a very costly exercise when it goes wrong and it will. You can see our dedicated page on the Dry-flex Wood Care System

What to do when you find rot

When something has had rot it needs cutting out, you wouldn’t keep a gangrenous leg would you? This is why we take all the paint off, even just black water stains can hide the dreaded rot underneath and this can only be found with an examination with a bradawl and knowing what to look for.

When paint has been layered on over the years it forms a very thick coat. If you have had water ingress in your sash windows it will stay in the wood because the wood is porous and the paint is not, It is meant to act as a barrier against the elements, and it is doing its job but the wrong way round and keeping the water in your windows causing more damage.

Next we would cut all the rotten timber out carefully until we get to good yellow colour on the wood with a tight grain. If the rot is too much and cannot be fixed using Dry-Flex (which is specially designed for window refurbishment and restoration), as explained before, you will have had water ingress and spread.

Window Constuction

We would look at what mortice and tenant joints that have been used around the affected area on the joints and duplicate these to the millimetre. Sometimes there isn’t that much left of the stile and the bottom bar of the windows, but with splicing timbers down the side of the stile and fixing using Polyurethane glue and doweling then we can reconstruct the windows back to how they were. Using Dry-Flex wood-care system it’s possible to bring your window back to life.

components of a sash window construction for sussex sash window restoration
this picture shows the components of a sash window.

After splicing the stiles we would start to look at the bottom bar or the meeting rail because this is where all the weight is on the window. The joints are always the same when they are constructed in the middle/ late Victorian period, they will have had horns on the top of the bottom window or the bottom of the top sash were the stile meets the meeting rail as the trend was rather regimented. The Regency period had a different way of constructing windows without horns so you would use triangle shaped tenants in the joints. This is a bit more complicated when stripping the windows apart but is just as good they only changed the design because of the weight of the glass and the expanse was getting bigger.

Once we have made the bottom bar/ mid rail with the original mouldings then we would start to put the windows back together again using Polyurethane glue, Dry-Flex and doweling. The glues have a working time of minutes and sometimes need two people to reconstruct the sash windows when you are dealing with very large windows or Georgian sash windows to get all the measurements correct. This is because if one of the glazing bars is out by just 1mm it can throw all of the vertical/ horizontal glazing bars out and create a bow in the window that will be most noticeable when you are admiring the view out of your window because everything is in straight lines.

Then we will usually have to re-glaze the restored sash windows and paint it to the spec that we have arranged with the client. The puttys should not be painted for at least 2 days even when we use certain materials to speed up the process of the putty curing.

Can I restore my sash windows

This method is not an easy process and needs someone that is very skilled in carpentry and joinery to reconstruct your sash windows especially when you have to splice timbers to the glazing bars without them showing. With the constructing of bowed Georgian sash windows, only experience and old school knowledge can make sure that the windows are properly made and work. This is one of the reasons I personally restore the sash windows myself and anyone that we are training up is under constant supervision until they can show that they can restore & construct any sash window that we could come across and this takes a lot of time even for qualified carpenters and joiners

Workshop Facilities

We have our own dedicated workshop facilities if we need to take away the windows and they require a little bit more time to cure. Because we use 3 different types of Dry-Flex, all having a different curing times sometimes we may need to board up the window as a last resort, but this can turn around in 24hrs but we do give a 48hr turnaround promise when we have to take them away due to us manufacturing new glazing bars, stiles, mid rails or bottom bars to your required mouldings but when this happens we do the glazing and painting at the same time so when you get your restored sash window back, it’s like new again, but better and that’s a promise

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