Greater London · England
Kings Cross External Mastic
Our applicators work in Kings Cross on sealing brickwork movement joints, render, cladding and façade joints. Old material cut out, joints cleaned and sealed neatly and a 12-month guarantee.
- Weathered mastic that no longer stretches
- Moss and dirt in joints with no sealant left
- Water getting into walls through failed joints
How we handle external mastic in Kings Cross
A movement joint is only as good as its depth. Closed-cell backing rod sets the depth and stops the sealant sticking to the back, leaving it bonded to two faces so it can move with the wall. We work on brickwork movement joints, façade panels and joints between brick and frames, and common reasons people get in touch are damp patches traced to an open external joint and sealant that has lost its bond to the brick or render.
Modern London flats rely on sealed movement joints and cladding joints. Older terraces have their own weak points: gutter joints, roofline trims and the joint where an extension meets the original wall.
All our work comes with our one-year guarantee, wherever you are in Greater London.
- Where
- Kings Cross (NW1W, NW1, N1)
- Region
- Greater London
- Guarantee
- 12 months on all our work
- Price
- Quoted before any work starts
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
Kings Cross: your questions answered
Is Kings Cross in your area for external mastic?
Yes. Our work covers London and the South East, and Kings Cross is part of that. Just phone 0345 464 0079 or drop us an email with a few details of the job, and we will give you a clear quote.
Do you work for landlords with property near London Kings Cross station?
Yes, landlords and agents are among the people we work for, and several properties can go on one quote. Just ring 0345 464 0079 or email us with the address and what needs doing, and we will give you a clear price.
Can you do several jobs on one visit?
Yes. Just list everything you need.
Do you seal joints where cladding meets other materials?
Yes. Materials like render, brick, metal and uPVC all move differently, so the joint between them must be flexible. The sealant is matched to both sides.
When will the joints need doing again?
That depends on the wall, the weather and the movement. Look for splits, hardening or edges coming away, and reseal at that point.
Which products do you use?
Quality sealants from brands including Arbo and Everbuild, chosen to suit the joint. We explain the product when we quote.
How long does the job take?
Most jobs take anything from a few hours to several days, depending on the building, including the preparation. We’ll confirm how long when we quote.
Can you work on commercial sites?
Yes. We work in offices, washrooms, hotels and other commercial premises, as well as homes. Working times can be discussed when we quote.
Why act early in Kings Cross
A properly done movement joint is an even line in a colour that suits the wall. A hurried job with smeared edges and no backing looks worse and fails sooner, so it pays to do it properly once. In older London homes, water behind a failed joint soaks into brick and timber without much sign, and by the time it shows on a wall or ceiling in Kings Cross, the repair is bigger than the sealant job would have been.
Instead of a standard rate, we look at what your job involves: the amount of work, the old material and the access. The price is agreed before we begin.
Why book with us
- A sealant colour to suit the surroundings
- Approved under the ARBOMaster scheme
- Domestic, commercial and hotel work
- 20+ years of sealant experience
DIY versus a professional finish
Too much sealant is as bad as too little. A heavy bead looks messy and copes badly with movement, and getting the depth right matters as much as the look.
The difference is mostly in the preparation and the product. Joints are cleaned back to sound surfaces and dried, and the sealant is matched to the joint and its conditions, then guaranteed for a year.
Signs you need external mastic in Kings Cross
Every building moves. Brickwork grows a little over the years, blockwork and concrete shrink, and all of it moves with heat and moisture. The sealant in the movement joints takes that strain.
These are the problems we are asked about most:
- Movement joints with cracked, split or missing sealant
- Moss and dirt in joints with no sealant left
- Sealant that has lost its bond to the brick or render
- Rain getting behind render or cladding at a joint
Kings Cross is in London, so parking needs planning: let us know about parking bays, permits or a driveway.
Before booking anyone
- Is the old sealant removed completely?
- How much experience the applicator has
- Which sealant they’ll use, and why
- Are they insured?
What affects the cost of external mastic
Every job gets its own quote. These are the things that affect it:
- Access and height
- Any working-time requirements on site
- How many rooms, windows or areas are involved
- The number and length of the joints
The cost depends on the amount of work, how hard the old material is to remove and access to the work. You’ll have a clear quote before any work starts.
What to tell us for a quote
A few details help us give you an accurate quote. When you ask for a quote, tell us:
- Where the job is, and your postcode
- Photos by email, if that’s easy
- How many joints, rooms or windows are involved
- Any access issues, like height or stairs
Need a quote? Please ring 0345 464 0079 or email us with a few details. We will explain what we’d do and give you a clear quote before we start.
Keeping the joints in good condition
Once the sealant has cured, a few habits help it last:
- Leave the joints unpainted unless we’ve said otherwise
- Act on the first splits you see
- Keep soil, plants and ivy away from the joints
- Show decorators and builders where the movement joints are
If you have more work done on the wall, such as new render, cladding or an opening, show the contractor the movement joints. They must stay as flexible joints, never rendered or pointed over.
Once a joint cannot move, the wall finds another way, normally as cracking in the brickwork or render nearby. Catch it early and you reduce the risk.
Landlord and commercial work in Kings Cross
If you manage several properties in or around Kings Cross, jobs at different addresses can go on one quote. Send us the addresses and the work at each.
We also work for businesses, from offices to washrooms and kitchens. On commercial sites, working times can be discussed when we quote.
Kings Cross buildings and the weather
Rainfall in the South East is lower than in much of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind. In terraces and conversions, gutters and walls are often shared with the neighbours, so it’s worth agreeing who is responsible before work starts.
Managing a site like Argyle Primary School? Then its movement joints, gutters and trims need looking after like any other building’s. Rented homes near London Kings Cross station change hands often, and failed wall and movement joints let damp in, so they’re worth checking between tenancies.
Kings Cross is about 1 mile north-west of St Pancras, in Greater London. For external mastic in and around Kings Cross, it’s easy to get a quote: please phone 0345 464 0079 or send us an email. We cover Greater London from our Crawley base, Kings Cross included. Our area takes in 764 places across Greater London, from the larger towns to small villages.
Every address in NW1W, NW1 and N1 is within our area for external mastic, from the main roads to the quietest streets. We cover properties on Euston Road, Duke's Road and Phoenix Road and the roads around them. Main roads around Kings Cross include the A501 and A4200, which makes travel easy. We also cover Somers Town (1 mile west), St Pancras (1 mile south-east), Euston (1 mile south-west), Bloomsbury (1 mile south) and Agar Town (1 mile north-west). We also work in nearby towns such as Kensington (4 miles south-west), Walthamstow (6 miles north-east), Whitechapel (3 miles east), Hampstead (3 miles north-west), Ruislip (13 miles west) and Brompton (3 miles south-west).
Near you in Kings Cross
In Kings Cross, that means homes and buildings near The Fellow pub, Lewis Cubitt Park and Pilsudski Institute of London. Nearby too are Regent High School (0.5 miles north-west) and The Poor School (within half a mile east). Kings Cross has its own railway station: London Kings Cross station. Well-known places in the area include Sartorial Contemporary Art (under half a mile south-east) and Brunswick Centre (less than half a mile south). Open spaces near Kings Cross include St. James's Park Lake and Ludgate Hill.
Towns and villages near Kings Cross
Also in Kings Cross
The process
You do not need to clear the whole room or building before we come, only the area right around the joints. Everything nearby is protected, and the job takes a few hours for a handful of joints, longer for a whole elevation for a typical job. In Kings Cross, as in most of London, parking needs a little planning. It helps if you can point us to a visitor permit or a bay close to the door.
- Each joint is checked and the colour of the new sealant agreed.
- Failed sealant is removed back to clean, sound faces.
- Closed-cell backing rod is pushed in so the sealant bonds to two sides only.
- We prime the faces where required.
- We gun in low-modulus sealant and tool it neatly.
Before we arrive
- For indoor joints, keep the area dry beforehand if you can
- Mention any parking rules near the property
- Tell us about any previous sealing or DIY attempts
Ask for a quote
We quote each job on its own, so the first step is telling us about yours. Just call 0345 464 0079 or drop us an email with the details.