Greater London · England
External Mastic in Seven Sisters
Movement joints in Seven Sisters need attention? We remove the old material, prepare the joints and seal them properly, with a 12-month guarantee.
- Joints where the bead has come unstuck
- Plants rooting in failed movement joints
- Joints pointed up with cement by mistake
External mastic in Seven Sisters, done properly
A movement joint is only as good as its depth. Backing rod controls how deep the sealant goes and keeps it off the back of the joint, leaving it bonded to two faces so it can move with the wall. If you have plants rooting in failed movement joints and rigid filler in a joint that should flex, we can put it right, whatever the surface.
Outside work in London starts with access: side passages, upper floors and where to park. In Seven Sisters, joints up high may need ladders or other access, which is worth talking through when you book.
You get a 12-month guarantee, the same in Seven Sisters as everywhere else we work.
- Location
- Seven Sisters (N15, N17, N16)
- Wider area
- Greater London
- Cover
- A year, on every job
- Quotes
- Quoted before any work starts
- Call
- 0345 464 0079
- Updated
- 26 October 2026
Should I try it myself first?
Sealing over old silicone is the commonest DIY error. Silicone doesn’t stick to old silicone, so it lifts and traps water and mould underneath. Everything old must be removed first.
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 doesn’t work out, we can still put it right.
FAQs for Seven Sisters
Can you help a landlord with a rental near Seven Sisters station?
Yes, landlords and agents are among the people we work for, and several properties can go on one quote. You can phone 0345 464 0079 or drop us an email with the details for a clear quote.
Is parking an issue for external mastic in Seven Sisters?
London parking needs a little planning, so let us know about permits, bays or a driveway when you book. That way the visit can be planned around it.
Is it OK to seal over old sealant?
No. The old sealant always comes out first, so the new joint bonds to clean surfaces.
What colours does the sealant come in?
We choose a sealant colour to suit the brick, stone or render so the joint blends in. Exterior sealants come in a good range of colours.
Do you have insurance?
Yes, we are fully insured for domestic and commercial work.
Can you seal joints between two different materials?
Yes. Where different materials meet is one of the most common joints we seal. We use a flexible sealant suited to both surfaces.
Do you remove the old sealant?
Yes. We cut out all the old sealant and clean the joint.
Can a movement joint be filled with mortar?
No. Mortar locks the joint solid, so the movement cracks the wall elsewhere. It needs a flexible sealant over backing rod.
Places near Seven Sisters
More services for Seven Sisters
How the visit works
Good joint work is mostly preparation, and we do not rush it. Joints are cleaned back and dried before anything new goes in. In total, it usually takes a few hours for a handful of joints, longer for a whole elevation. In Seven Sisters, 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.
- We start by checking each joint, agreeing the ones to redo and how we will reach them.
- The old mastic and anything lodged in the joint is removed.
- The joint faces are cleaned and primed where the sealant needs it.
- Backing rod goes in next, setting the depth and keeping the sealant off the back of the joint.
- The new sealant, chosen to suit the brick or render, is applied and tooled to a neat finish.
How to prepare
- Keep children and pets away from the work area
- Clear the area around the work
- Where the joints are inside, avoid wetting them before we arrive
Get a quote
We quote each job on its own. Simply phone 0345 464 0079 or send us an email and describe the job.
Related advice
Aftercare tips
After the cure time, these simple habits help:
- Clear growth from the base of walls and joints
- Walk round the building once a year and look at the joints
- Point out the joints to other trades
- Keep high-pressure jets off the joints
Only paint over the joint if we have confirmed the sealant can take paint. Paint can crack on a flexible joint, and paint can crack as the joint moves.
Leave a failed movement joint and water keeps getting into the wall. That can lead to damp patches, staining and frost damage which cost more to put right than the joint.
Surface by surface
Render joints
The face of render can be soft, so a low-modulus sealant is kinder to the joint edges. Priming is done where the sealant calls for it.
Cladding and façade panels
Metal and composite panels move a lot with temperature, so the joint sealant has to cope with frequent movement. We choose the product to suit.
Seven Sisters buildings and the weather
London and the South East are among the drier parts of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day. With historic houses such as Bruce Castle (about 1.2 miles north) nearby, there’s older building stock in the area around Seven Sisters 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.
Homes close to Church of Holy Trinity include some older properties, and the joints between older walls, newer extensions and the roofline need a sealant that can move. Managing a site like Earlsmead Primary School? Then its movement joints, gutters and trims need looking after like any other building’s.
Seven Sisters is about 2 miles west of Walthamstow, in Greater London. Anywhere in N15, we cover external mastic for homes and businesses. Seven Sisters is one of 764 places in Greater London we cover for external mastic. London is on our list too, around 6 miles away.
Every address in N15, N17 and N16 is covered for external mastic. We cover properties on Ida Road, Elmar Road and Grove Road and the roads around them. We also cover the places around Seven Sisters: South Tottenham (1 mile north), Tottenham Green (1 mile north), St Ann's (1 mile west), Tottenham Hale (1 mile north-east) and West Green (1 mile west). Further out, we also cover London (6 miles south), City of Westminster (6 miles south-west), Marylebone (5 miles south-west), Kensington (8 miles south-west), St Pancras (4 miles south-west) and Shoreditch (4 miles south).
Near you in Seven Sisters
Around Seven Sisters, our work takes us to homes and buildings near No.8 Seven Sisters pub, Ada College and Chestnuts Park. Other local landmarks include Gladesmore Community School (less than half a mile east) and Church of St Andrew (0.8 miles south). There’s a railway station in Seven Sisters itself: Seven Sisters station. Other landmarks nearby include Montfichet's Tower (4.9 miles south) and The Mall Wood Green (1.7 miles north-west). Open spaces near Seven Sisters include Highgate Hill and Woodberry Wetlands.
When something else is needed
We won’t take on work that will not last, so here’s what sealant cannot put right:
- Cutting new joints into brickwork, which is building work rather than sealant work
- Subsidence or other structural problems
- Loose or hollow render, which needs re-rendering
Not sure which it is? You can ring 0345 464 0079 or drop us an email and we’ll tell you honestly before booking.
What we seal
- Joints between brick and frames
- Concrete & block
- Façade panels
- Brickwork movement joints
- Copings & trims
- Render & cladding joints
For landlords and businesses
We work for letting agents and landlords as well as homeowners. Resealing between tenancies keeps a property looking cared for before the next move-in.
Mouldy or split sealant often shows up at the end of a tenancy. We can quote for more than one property at once.
What we are called out for in Seven Sisters
Buildings move more than people expect. 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.
Signs it’s time to call us include:
- Rigid filler in a joint that should flex
- Moss and dirt in joints with no sealant left
- Movement joints with cracked, split or missing sealant
- Rain getting behind render or cladding at a joint
As a London address, Seven Sisters can be tricky for parking: let us know about parking bays, permits or a driveway.
Before you book anyone
- What the quote includes, VAT included or not
- When the joint can take water or movement
- The length of the guarantee
- Whether the sealant suits the joint