Greater London · England
External Mastic in Crystal Palace
Sealing brickwork movement joints, render, cladding and façade joints for homeowners, landlords and businesses in Crystal Palace. ARBOMaster approved applicators, fully insured, with a 12-month guarantee.
- Sealant pulling away from one side of the joint
- Brick movement joints where the sealant has split
- Rain getting behind render or cladding at a joint
What external mastic looks like in Crystal Palace
Historic houses like Kingswood House (about 0.9 miles north-west) are a reminder that the area around Crystal Palace has older buildings as well as new. In older buildings, older walls and rooflines need a sealant that moves with them and suits the material. In terraces and conversions, gutters and walls are often shared with the neighbours, so check who is responsible for the outside before booking.
If you live in an older home near St Paul's, old and new materials meet at the roofline and walls, which is where sealant earns its keep. Rented homes near Crystal Palace station change hands often, and outside joints that have cracked can let damp into a rental, so check them between lets.
Crystal Palace is about 2 miles north-east of Thornton Heath, in Greater London. We carry out external mastic for homes and businesses in Crystal Palace. Across Greater London, we cover 764 places, Crystal Palace among them. You can also see our page for London, about 6 miles away.
We work across the SE19, SE20 and SE26 postcode area for external mastic and the streets around it. You will find streets such as Tudor Road, Colby Road and Church Road, all of which we cover. We also cover the places around Crystal Palace: Anerley (1 mile south), Penge (1 mile south-east), Gipsy Hill (1 mile west), Upper Norwood (1 mile west) and Sydenham (1 mile north-east). Further out, we also cover London (6 miles north), City of Westminster (7 miles north-west), Marylebone (7 miles north-west), Kensington (8 miles north-west), St Pancras (8 miles north) and Shoreditch (7 miles north).
Landmarks near Crystal Palace
In Crystal Palace, that means homes and buildings near The Grape & Grain pub, Crystal Palace Park and Sydenham High School, among other places. There’s a railway station in Crystal Palace itself: Crystal Palace station. Nearby you will also find Greenwich Castle (5 miles north-east) and Whitgift Centre (3.3 miles south-west). Not far away are Dulwich Upper Wood and Knight's Hill.
How we handle external mastic in Crystal Palace
Joints between dissimilar materials, like brick against render or concrete against a steel frame, see movement from both sides. A flexible sealant bridges the two where mortar or filler would crack. Typical jobs include weathered mastic that no longer stretches and joints pointed up with cement by mistake, across render & cladding joints, concrete & block and brickwork movement joints.
Working on the outside of a London home means planning access: shared paths, upper floors and parking. In Crystal Palace, joints up high may need ladders or other access, which is worth talking through when you book.
We stand behind the work with a one-year guarantee.
- Location
- Crystal Palace (SE19, SE20, SE26)
- Region
- Greater London
- Cover
- 12 months on all our work
- Quotes
- A clear quote up front
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
Do you need external mastic in Crystal Palace?
Some movement joints have been pointed up with mortar. With the joint locked solid, the movement turns into cracks elsewhere in the wall.
Common reasons people contact us are:
- Movement joints filled with mortar instead of sealant
- Rain getting behind render or cladding at a joint
- Sealant that has lost its bond to the brick or render
- Cracked joints where brick meets render or frames
Managing a site like Crystal Palace School? Then its movement joints, gutters and trims need looking after like any other building’s.
Questions to ask before booking
- Who turns up on the day
- How the surfaces are prepared before sealing
- What the quote includes, VAT included or not
- What happens if the job turns out different
Your questions about external mastic in Crystal Palace
Do you work for landlords with property near Crystal Palace station?
Yes, landlords and agents are among the people we work for. You can phone 0345 464 0079 or drop us an email with the details for a clear quote.
Can you do external mastic in Crystal Palace?
Yes. Our work covers London and the South East, and Crystal Palace is part of that. You can phone 0345 464 0079 or email us and let us know what needs doing, and we will give you a clear quote.
Does someone need to be in?
Access is agreed with you when the job is booked. Indoors, that usually means someone at home.
How often do external joints need resealing?
It varies with how exposed the wall is and how much the joint moves. Signs to watch for are cracking, hardening and gaps at the edges.
Why is there a gap in my brick wall?
Brickwork, render and cladding all move a little, so long walls have planned gaps to take that movement. The gap is sealed with a flexible sealant over backing rod.
What do you need from me for a quote?
The location, the problem and the rough size of the job. If you can, email a few photos.
What is backing rod for?
Backing rod goes into deeper joints as a matter of course. It sets the sealant depth and prevents three-sided bonding so the bead can stretch.
Where is Mr Mastic based?
We’re based in Crawley, and we work across South East England, London and Scotland.
Also near Crystal Palace
What else we do in Crystal Palace
Work for landlords, hotels and businesses
A neglected joint can let water reach the structure, which is a bigger problem in a rented property. Resealing at the right time is simple maintenance.
Housing providers, facilities teams and property managers book us too in Crystal Palace and across Greater London. Several sites can go on one quote, and we are fully insured.
What affects the cost of external mastic
Jobs vary more than people expect. What affects the quote:
- The size of the job
- How many rooms, windows or areas are involved
- How easy the joints are to reach
- Whether there’s mould to deal with
The cost reflects the work involved, not a rough estimate. That’s why we ask a few questions first and agree the price before starting.
What to tell us for a quote
A few details help us give you an accurate quote. When you get in contact, it helps to mention:
- If it’s domestic, commercial or a hotel
- If someone has resealed it before
- Any access issues, like height or stairs
- A few pictures by email, if you can
If you are in Crystal Palace and need external mastic, phone 0345 464 0079 or drop us an email. A short description of the job and where it is helps us quote, and we’ll agree the price before any work begins.
How to look after the new joints
How long the joints last depends on use and care. Here’s what we suggest:
- Clear growth from the base of walls and joints
- Keep movement joints as flexible joints, not mortar
- Keep water from gutters off the wall
- Act on the first splits you see
Have a quick look at the joints each spring. Watch for splits, edges coming away or growth in the joint.
Leave a failed movement joint and water keeps getting into the wall. Over time it can mean damp inside, stained render or frost-damaged brick which cost more to put right than the joint.
DIY sealant or a professional job?
A careful DIYer can reseal a simple joint, like a short, easy-to-reach joint indoors. Where it goes wrong is sealing over the old bead, working on a wet joint or overloading the gap.
If you’ve already had a go yourself, that is fine. We remove it and do the joint properly.
Honest limits
In fairness, some problems need a different trade:
- Structural movement, which needs a surveyor or engineer
- Rising or penetrating damp from elsewhere in the wall
- Walls that need new movement joints cut into them
Not sure which it is? You can ring 0345 464 0079 or email us and we will tell you honestly before you book.
Where we work in Crystal Palace
- Concrete & block
- Joints between brick and frames
- Copings & trims
- Brickwork movement joints
- Render & cladding joints
- Façade panels
What we do, step by step
When we arrive, we start by going over the job with you, so there are no surprises. Surfaces next to the work are protected before any work begins. The work normally takes anything from a few hours to several days, depending on the building. In a London area like Crystal Palace, the main things to plan are parking and access: let us know about parking, the floor we’ll be working on and any lift or shared entrance.
- First we look over the joints with you, agree which to renew and talk through access.
- Old sealant and any debris are cut and raked out.
- The joint faces are cleaned and primed where the sealant needs it.
- Closed-cell backing rod is fitted to set the depth and stop three-sided bonding.
- We gun in a flexible exterior sealant in a colour that suits the wall and tool it neatly.
Before we arrive
- Tell us about any previous sealing or DIY attempts
- Clear the area around the work
- Where the joints are inside, avoid wetting them before we arrive
Get a quote
We don’t publish a price list, because every job is different. Instead, we send you a clear quote for your job. To arrange one, call 0345 464 0079 or drop us an email.