Greater London · England
External Mastic in Lower Holloway
External mastic for Lower Holloway, by sealant specialists with 20+ years’ experience. 180+ five-star Google reviews and a 4.9 rating.
- Damp patches traced to an open external joint
- Weathered mastic that no longer stretches
- Joints where the bead has come unstuck
External mastic in Lower Holloway
Joints in render and cladding are easy to overlook until a damp patch appears. We inspect them, agree which need doing and reseal with a weatherproof, flexible sealant. If you are dealing with old sealant gone brittle and cracked and joints pointed up with cement by mistake, we can help, whatever the surface.
Newer London blocks are built with movement joints in brick and render, and with cladding joints sealed with mastic. Period houses have different weak points, such as gutter joints, trims and the line where an extension meets the old wall.
You get a 12-month guarantee, the same in Lower Holloway as everywhere else we work.
- Where
- Lower Holloway (N7, N1, N5)
- Region
- Greater London
- Cover
- 12 months on all our work
- Quotes
- A clear price before work begins
- Call
- 0345 464 0079
- Updated
- 26 October 2026
Landlord and commercial work in Lower Holloway
We also work for businesses, from offices to washrooms and kitchens. For commercial premises, we can talk through working times when we quote.
Water getting past a failed joint can damage the building, which is a bigger problem in a rented property. Resealing at the right time is simple maintenance.
Different surfaces, different methods
Render joints
Water behind render can lead to blown patches. Resealing the joints early keeps water out.
Joints between dissimilar materials
Each side of the joint may need its own preparation. Both surfaces are cleaned and primed as the product requires.
What we do, step by step
Every visit runs the same way: we look at the joints together, mask and protect the surrounding surfaces, do the work and tidy away. It usually takes a few hours to a few days, depending on the length of joint and the access. In a London area like Lower Holloway, the main things to plan are parking and access: tell us about permits, visitor bays or off-street space, which floor we are working on and whether there’s a lift.
- First, the joints are inspected and the access agreed.
- We cut out the old mastic and rake out anything in the joint.
- The faces are brushed clean and primed where the product requires it.
- We fit closed-cell backing rod to control the depth.
- The exterior sealant is applied, tooled and checked along its length.
Preparing for the visit
- Let us know about parking restrictions
- Keep children and pets away from the work area
- Mention if the joints have been sealed before
How to get a quote
Quotes start with a quick conversation. Tell us what’s wrong, where it is and how much there is, and we will explain how we’d tackle it. When it suits you, phone 0345 464 0079 or drop us an email.
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Towns and villages near Lower Holloway
Also in Lower Holloway
Questions from Lower Holloway
I let a flat near Caledonian Road & Barnsbury station. Can you help?
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’ll send you a clear quote.
Is parking a problem for a job in Lower Holloway?
London parking needs a little planning, so let us know about permits, bays or a driveway when you book. The visit is then planned around what’s available.
What should I tell you?
Just the basics: the address or postcode, what’s wrong and any access issues. Then ring 0345 464 0079 or drop us an email.
Do I have to be there?
If the work is inside, we need someone to let us in. Once we have agreed the job, you do not need to watch us work.
Do you cover Lower Holloway?
Yes. We work in Lower Holloway. To book, call 0345 464 0079 or send us an email.
Do you have insurance?
Yes. We’re fully insured.
How long does external mastic last?
There’s no fixed answer: sunny, exposed elevations and busy joints wear faster. A yearly look will tell you when they need doing. Our work comes with a 12-month guarantee.
When is the sealant fully cured?
Most sealants are touch-dry well before they’re fully cured. We will tell you how long to leave the joint.
Signs you need external mastic in Lower Holloway
Many joints fail because they were sealed too deep or with nothing behind them. If the sealant sticks to the back as well as the sides, it cannot stretch and rips as the joint opens.
People generally contact us when they notice one of these:
- Old sealant gone brittle and cracked
- Plants rooting in failed movement joints
- Damp patches traced to an open external joint
- Joints with sealant missing in places
As a London address, Lower Holloway can be tricky for parking: tell us about permits, visitor bays or off-street space when you book.
Comparing quotes
- What happens if they find a problem under the old sealant
- When the joint can take water or movement
- How the joint is cleaned and prepared
- Who does the work, and how experienced they are
DIY versus a professional finish
Some sealant jobs are within reach of a careful DIYer, such as a straightforward joint indoors. The common mistakes are sealing over old sealant, sealing a damp joint and using far too much.
Not every job suits DIY: high-level joints, fire-rated gaps, external movement joints and big jobs need the right product, the right access and the right method.
External mastic in Lower Holloway: local notes
Compared with the north and west, the South East gets less rain, 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.
If you look after a building such as Sacred Heart Catholic Primary School, larger buildings have long runs of movement joint that eventually need resealing. In the older streets around St David, an extension built onto an older house moves differently, and the joint between them takes the strain.
Lower Holloway is about 2 miles north of St Pancras, in Greater London. Across the N7 area, we can carry out external mastic at your property. Lower Holloway is one of 764 places in Greater London we cover.
Here we cover the N7, N1 and N5 postcode area for external mastic. Whether your property is on Penn Road, Cliff Road and Lough Road or a nearby road, we can help. With the A5203 close by, Lower Holloway is easy for our applicators to reach. If you’re just outside Lower Holloway, we cover Barnsbury (1 mile south), Holloway (1 mile north), Nag's Head (1 mile north), Tufnell Park (1 mile north-west) and Islington (1 mile south-east). Further out, we also cover London (4 miles south), City of Westminster (3 miles south-west), Marylebone (3 miles south-west), Kensington (5 miles south-west), Walthamstow (5 miles north-east) and Whitechapel (3 miles south-east).
Landmarks near Lower Holloway
Typical jobs here are in homes near St Mary Magdalene Gardens, Musical Theatre Academy and St Mary Magdalene Academy. Other local landmarks include Vaughan Williams Memorial Library (1.6 miles south-west) and The Lamb Tavern Public House (within half a mile west). The closest station to Lower Holloway is Caledonian Road & Barnsbury station, about 0.5 miles south of the centre. Nearby you will also find Arsenal Football Club Museum (0.6 miles north-east) and Montfichet's Tower (2.6 miles south). Green spaces nearby include Dartmouth Park Hill and Barnsbury Wood.
When it isn’t the sealant
We’d rather tell you now than do work that will not last, so these are the limits:
- Cracking across the wall rather than at a joint
- Loose or hollow render, which needs re-rendering
- Rising or penetrating damp from elsewhere in the wall
If you are not sure, just call 0345 464 0079 or email us and we will give you a straight answer before you book.
Where we work in Lower Holloway
- Joints between brick and frames
- Render & cladding joints
- Façade panels
- Concrete & block
- Copings & trims
- Brickwork movement joints
Looking after it afterwards
Aftercare is simple, and it makes a real difference:
- Act on the first splits you see
- Ask before painting over external sealant
- Point out the joints to other trades
- Wash walls gently around the sealant
Have a quick look at the joints each spring. Watch for splits, edges coming away or growth in the joint.
Gaps, plants or missing sealant in a joint are worth getting looked at. Early work is quicker and leaves a better finish.