Womersleys Burnt Sand Mastic

Womersley's Burnt Sand Mastic is ideal for pointing around windows and doors (timber or metal). Burnt sand mastic adheres tenaciously to most surfaces and has been used for over 200 years in building construction and renovation. At Womersley’s we follow the traditional method of preparation by roasting fine silver sand and supplying with British Wax linseed oil which has been double boiled with rosin driers added. Designed to harden slowly but remain flexible, Burnt Sand Mastic efficiently reduces the risk of cracking when forming joints.

Preparation:

Before pointing ensure that all wide gaps between the frames and the masonry are tightly packed with Ironstone Pre mixed or haired lime mortar,allow to cure and harden. If the masonry has a high surface absorbency use tape to protect  against undue surface spread.

Timber frames should have flaking paint removed and be fully primed and undercoated before applying the finished mastic.

Application:

Burnt sand mastic is a two-part product. For each litre of burnt sand add approximately 250ml of the double boiled linseed oil hardener. Add only a little at a time and mix until the mastic forms a thick putty like consistency, which comes cleanly off the mixing trowel. Let the mix stand on a board for 15 minutes and use any excess oil which runs off plus any remaining oil as a primer, applied with a brush to the frame and adjoining masonry. 

Apply the mastic whilst the primer still feels oily or tacky to touch. Press the mastic firmly into the angle of the frame / jamb and filling from the bottom up, forming the mastic joint to a neat 45 degree angle.

Keep tools wiped with an oiled cloth during the application. After forming the angle, starting from a corner, press a clean oiled mastic trowel tightly against the face of the timber frame and masonry jamb and carefully press and draw the trowel to create a neat regular fillet. Clean away any excess mastic and wipe the finished edges on completion. For mastic to sills, ensure the mastic does not bridge any drips and is left recessed behind the drip check. Mastic should not be over painted. Mastic fillets should be neat 20 - 25mm across the diagonal face

Womersley’s Burnt Sand Mastic is available in Buff, Red, Yellow, Cream and Umber

Coverage = 10L Tub Approx' 30 linear meters with to a 20-25mm fillet