Mastic & Sealant Replacement
Most sealant failures are not material failures. They are joint design and preparation failures — wrong depth, no backing rod, no primer, three-sided adhesion.
We remove failed sealant back to sound substrate, prepare and prime correctly, install the right backing rod and joint geometry, and apply a sealant selected for the substrate, the movement it has to accommodate and the exposure it will face.
ARRT Group is SafeContractor accredited and can offer an insurance-backed guarantee of up to 20 years on the work.
Scopes range from single perimeter joints to whole-elevation reseals across panel joints, movement joints, glazing perimeters and penetrations — most of it delivered on rope access with no scaffold.
The same discipline applies to external sealing on glazed and heritage roofs, carried out at height while the building stays open. Named example: external sealing to the three major glazed roofs at Alexandra Palace, a Grade II listed London landmark, a live Grade II venue.
Where the leak is through the glazing gaskets rather than a sealant joint, see curtain wall gasket replacement. For resealing a leaking glass roof, see glass roof leak repair.
What we deliver
- Full removal of failed sealant and preparation to sound substrate
- Movement joint and panel joint resealing
- Glazing perimeter and weather seal replacement
- Structural silicone remediation
- Penetration, coping and interface sealing
- Substrate-specific priming and colour matching
How the work is done
| Joint types | Movement, expansion, panel, perimeter, penetration, coping |
|---|---|
| Substrates | Aluminium, glass, stone, concrete, render, composite panels |
| Materials | Silicone, hybrid polymer, polyurethane — specified per joint |
| Access methods | Rope access, MEWP, cradle, tower |
| Deliverables | Materials data sheets, photographic record, workmanship warranty |
Questions we get asked
Why did our last reseal fail after two years?
Nine times out of ten: no backing rod, incorrect joint depth, missing primer, or sealant applied over a contaminated substrate. Preparation is most of the job.
Can you colour match to our facade?
Yes. We match to the existing sealant or the frame finish, and confirm the colour with a sample on site before proceeding.
Often needed alongside this
High-Level Glass Replacement
Failed, cracked, blown or vandalised units replaced at height — from single panes to full elevations, with access designed around your building.
View service 02Curtain Wall Refurbishment
Extend the life of an ageing aluminium facade — gaskets, seals, drainage, fixings and finishes brought back to a serviceable, watertight standard.
View service 03Atrium & Rooflight Glazing
Overhead glazing repaired and refurbished over live public space — with the temporary works, protection and rescue planning that overhead work demands.
View service
Need a specialist on site?
Send us the building, the defect and a photograph if you have one. We will tell you the access method, the likely scope and a realistic programme.