Mastic & Security


Mastic is the seal between the window and the fabric of the building, which keeps out the wind and rain. As soon as this seal starts to decay, water ingress can begin and can cause many problems inside the building. SashWindowCraftsman have over 25 years’ experience in this specialised field, we aim to ensure that every sash window that we repair or replace is sealed properly.

There are different types of mastic which need to be used for specific buildings. Listed buildings, for example, require traditional burnt sand mastic to be applied. When a project requires this type of mastic, we use only the finest Masons Mortar products and apply this, using precise specifications.

For modern and non-listed buildings, we use a more flexible mastic, which has up to 20% movement accommodation and is ideal for sealing the area between the window and the stone. This flexible mastic is much more suitable, allowing for the timber to contract and expand without cracking and can also be painted over.

We can offer expert advice on any type of mastic, from traditional burnt sand mastic to the modern flexible mastics. Working with the most experienced mastic applicators in the country, we can offer professional advice and installation and all work is fully guaranteed.


Security is a prominent issue for every household and at SashWindowCraftsman, we offer several additional measures to ensure that you feel completely safe in your home.

Every sash window can come with:

  • Locking centre catches
  • Key operated security locks
  • Sash bolts
  • Sash limiters
  • Sash stops
  • Security glass

Our consultants are on hand to answer any security questions that you may have about sash windows and can offer helpful tips and guidance on keeping your home secure.

Contact Us

We offer a wide range of services. Please email us to schedule a consultation appointment, and we'll address your needs from there.