Greater London · England
St Giles External Mastic
External mastic for St Giles, by sealant specialists with 20+ years’ experience. Rated 4.9 on Google from 180+ five-star reviews.
- Hard, crazed mastic that has stopped moving
- Rain getting behind render or cladding at a joint
- Cracked joints where brick meets render or frames
Looking after it afterwards
Simple care keeps the joints in good condition. Our advice:
- Wash walls gently around the sealant
- Check the sealant is paintable before painting near it
- Have failed joints looked at early
- Look over the joints every year, ideally after winter
If you have more work done on the wall, such as new render, cladding or an opening, show the contractor the movement joints. They should be kept open and resealed, not filled.
Leave a failed movement joint and water keeps getting into the wall. That can lead to damp patches, staining and frost damage.
External mastic for homes and businesses in St Giles
On houses, flats and commercial buildings across St Giles, we reseal joints in brickwork, render, cladding and façade panels. The preparation is the same whatever the wall: clean, sound faces and a controlled depth. If you’re dealing with plants rooting in failed movement joints and joints pointed up with cement by mistake, we can help, whatever the surface.
London’s terraces and conversions often share walls, gutters and downpipes with their neighbours, so one failed joint can cause damp for more than one household. In a converted house in St Giles, it’s worth checking who is responsible for the outside before booking.
We stand behind the work with a 12-month guarantee.
- Where
- St Giles (W1F, W1D, W1T)
- Wider area
- Greater London
- Guarantee
- One year on every job
- Price
- Quoted before any work starts
- Phone
- 0345 464 0079
- Last updated
- 26 October 2026
Also near St Giles
Other services in St Giles
What external mastic looks like in St Giles
With historic houses such as Benjamin Franklin House (about 0.5 miles south) nearby, there’s older building stock in the area around St Giles as well as newer homes. Where a home is older, older brick and stone need a sealant that suits them, at the right joint depth. In terraces and conversions, gutters and walls are often shared with the neighbours, so it’s worth agreeing who is responsible before work starts.
In the older streets around Soho Baptist Chapel, the joints between older walls, newer extensions and the roofline need a sealant that can move. Rented homes near Tottenham Court Road station change hands often, and split movement joints are easy to miss on a rental until damp shows inside.
St Giles is about 1 mile east of City of Westminster, in Greater London. For external mastic in and around St Giles, it’s easy to get a quote: please phone 0345 464 0079 or drop us an email. We cover Greater London from our Crawley base, St Giles included. Across Greater London, we cover 764 places, St Giles among them.
Our applicators cover all of W1F, W1D and W1T for external mastic and the streets around it. Streets in the area include Duck Lane, Drury Lane and Bridle Lane, all of which we cover. Being close to the A301 and A400, St Giles is easy for our applicators to reach for external mastic. Close by, we work in Seven Dials (1 mile south), West End (1 mile south-west), Soho (1 mile south-west), Covent Garden (1 mile south-east) and Chinatown (1 mile south-west). Further out, we also cover Kensington (3 miles west), Walthamstow (7 miles north-east), Hampstead (4 miles north-west), Ruislip (13 miles west), Stockwell (3 miles south) and Orpington (13 miles south-east).
Landmarks near St Giles
Locally, jobs take us to homes and businesses close to LSE Shaw Library, The Crown pub and Mercers' School and the streets around them. Also close by are London Nautical School (1 mile south-east) and St Anne's Churchyard (less than half a mile south-west). St Giles has its own railway station: Tottenham Court Road station. A little further out are Montfichet's Tower (1.1 miles east) and Kingly Court (0.5 miles west). Open spaces near St Giles include Barnsbury Wood and Ludgate Hill.
When to call us in St Giles
Sometimes a movement joint was filled with mortar or a rigid filler, often by someone who didn’t know what it was for. With the joint locked solid, the movement turns into cracks elsewhere in the wall.
Signs it’s time to call us include:
- Movement joints with cracked, split or missing sealant
- Weathered mastic that no longer stretches
- Damp patches traced to an open external joint
- Cracked joints where brick meets render or frames
St Giles is in London, so parking needs planning: let us know about parking bays, permits or a driveway.
Comparing quotes
- How long the guarantee is
- Who turns up on the day
- How long to leave it before use
- What happens if they find a problem under the old sealant
What happens if it’s left?
Pointing a movement joint with mortar might seem a neat fix, but it locks the joint solid. The movement then cracks the brickwork or render nearby. The correct repair is a flexible sealant with the right backing. Damp from a failed joint spreads quietly in older London brickwork and timber, and once it shows in St Giles, the repair is bigger than a sealant job.
Homes and businesses are quoted the same way: the amount of work, the access and the products needed, plus any working-time requirements on site. Call for a quick quote and we’ll explain what it covers.
Why us?
- Experience in homes, commercial sites and hotels
- ARBOMaster approved applicator
- A sealant colour to suit the surroundings
- Fully insured
The process
When we arrive, we start by going over the job with you. We protect the surfaces around the joints before work begins. Most jobs take anything from a few hours to several days, depending on the building. In a London area like St Giles, the main things to plan are parking and access: tell us about permits, visitor bays or off-street space, which floor we’re working on and whether there’s a lift.
- We start by walking round the building and agreeing the joints and the access.
- We cut out the old mastic and rake out anything in the joint.
- Joint faces are cleaned back and primed if the sealant needs it.
- We fit closed-cell backing rod to control the depth.
- We apply the sealant, tool it and check the whole run.
Preparing for the visit
- Let us know about parking restrictions
- Clear items away from the joints we’re working on
- Let us know if you’ve seen damp or leaks
How to get a quote
If you are in St Giles and need external mastic, phone 0345 464 0079 or drop us an email. Tell us what the problem is and where, and you’ll get a clear quote before we start.
Related advice
Landlords, agents and businesses in St Giles
Housing providers, facilities teams and property managers book us too in St Giles and across Greater London. Several sites can be quoted together, and we are fully insured.
Letting agents often deal with us directly. Send the address, what’s needed and the access arrangements and we will quote.
How we quote for external mastic
You’ll get a clear quote before we start. It’s based on:
- Whether old sealant or filler has to be cut out
- When we can work, for business premises
- Access and height
- Whether there’s mould to deal with
The cost depends on the size of the job, how hard the old material is to remove and how easy the joints are to reach. You’ll have a clear quote before any work starts.
Asking for a quote
A few details help us give you an accurate quote. When you ask for a quote, tell us:
- The address or postcode of the job
- What’s wrong with the joints now
- Access, such as stairs, a lift or height
- Any previous sealing or DIY work
For a quote, ring 0345 464 0079 or drop us an email and tell us where the job is and what the problem looks like. You will have a clear quote before we start.
Can I do it myself?
If you do try it yourself, take your time over the preparation: take out all the old sealant, make sure the joint is clean and dry, and give it the full cure time. If it fails, we can still redo it.
A DIY attempt doesn’t rule out a professional job. We remove it and do the joint properly, so just mention it when you contact us.
Common questions in St Giles
Is parking an issue for external mastic in St Giles?
Parking in St Giles, as in most of London, takes a little planning: a visitor permit or a bay close to the door helps a lot.
I let a flat near Tottenham Court Road station. Can you help?
Yes, rental work is part of what we do. Just ring 0345 464 0079 or send us an email and tell us about the property, and we will give you a clear quote.
Should I point up the gap in my brickwork?
No. Rigid materials cannot move with the wall and the joint fails. Where a joint has been mortared, it can often be raked out and sealed properly.
How often do external joints need resealing?
It varies from wall to wall: sunny, exposed elevations and busy joints wear faster. Check them each year and reseal when they split or harden. Our work comes with a 12-month guarantee.
Do you work at height?
That depends on how high the joints are and the ground below. Ground-floor joints are simple; for higher ones, send details and we will confirm the access.
Do you seal joints where cladding meets other materials?
Yes. Joints between dissimilar materials are a big part of external work. The sealant is chosen to bond to both sides, primed where needed.
Is it OK to seal over old sealant?
No. New silicone won’t bond to old silicone, and it traps any mould or water underneath. It all has to come out first.
Do you take out the old sealant first?
Yes. All of the old material is cut out and the joint cleaned.