Greater London · England
Barnet Gutter Sealing
Gutter sealing for Barnet and the surrounding area: the right sealant, proper preparation and a neat finish. Call for a quick quote.
- Open joints in fascias and soffits
- Garage door frames letting rain in
- Water dripping where gutter sections meet
How we handle gutter sealing in Barnet
Gaps along uPVC fascias and soffits look untidy and can let in water and draughts. They’re sealed in a matching colour where one is available. If you have failed sealant on a garage door frame and wet patches on the wall under a gutter joint, we can help, whatever the surface.
Outside work in London starts with access: side passages, upper floors and where to park. For a home in Barnet, tell us how high the joints are and how to reach the back of the building.
The work is guaranteed for twelve months. If something isn’t right with it in that time, tell us and we’ll put it right.
- Where
- Barnet (EN5, EN4, N20, N11)
- Region
- Greater London
- Guarantee
- A year, on every job
- Price
- A clear price before work begins
- Call
- 0345 464 0079
- Last updated
- 26 October 2026
What the job involves on each surface
Roofline trims
Trims along the roofline are often finished with sealant. Split sealant lets water in.
Gutter joints
A gutter joint has to cope with movement and standing water. A dedicated gutter sealant suits them.
Can I do it myself?
A DIY attempt does not rule out a professional job. We remove it and do the joint properly.
The biggest DIY mistake is sealing over old sealant. Silicone doesn’t stick to old silicone, so it peels away and traps moisture behind it. Everything old must be removed first.
What affects the cost of gutter sealing
For a quick quote, just ask. The main things that affect it are:
- The old material and how stubborn it is
- Any working-time requirements on site
- The size of the job
- Any mould that needs treating
A failed joint rarely gets cheaper to fix by waiting, as water and mould keep getting in. If you are not sure whether it needs doing, ring 0345 464 0079 or send us an email and we will give you an honest view and a quote.
Asking for a quote
A few details help us give you an accurate quote. When you get in contact, it helps to mention:
- Access, such as stairs, a lift or height
- The rough size of the job
- Where the job is, and your postcode
- The problem you’ve noticed
Every job is quoted individually, so start by telling us what you need. Simply phone 0345 464 0079 or drop us an email and describe the job and send pictures if you have them.
Work for landlords, hotels and businesses
Whether it’s one flat or a portfolio, the work is the same standard: the old material taken out, careful preparation and a 12-month guarantee.
A neglected joint can let water reach the structure, which matters even more when someone else lives there. Resealing at the right time is simple maintenance that we can handle for you.
How to look after the new joints
Joint life depends on how it’s used and looked after. Here’s what we suggest:
- Watch for drips in a downpour
- Clear leaves and moss from the gutters
- Deal with a drip before winter
- Look along the fascias for open joints
Keep downpipes clear so the gutter can drain. A blocked pipe backs water up to the joints.
A drip from a gutter joint won’t stop on its own. Water keeps hitting the same part of the wall, which can lead to staining and damp.
How it works
At the end, we look at the finished work together and explain the cure time. The work normally takes an hour or two for a few joints, longer for a full run, depending on the size of the job. Parking in much of London is by permit or pay-and-display, so it helps to know what’s near you in Barnet. A visitor permit or a nearby bay makes the visit run more smoothly.
- We find where the water is coming from and check the gutter is sound.
- We remove the old sealant and clean the joint.
- The joint is dried before sealing.
- A gutter sealant is applied to the joint.
- We check the run and clear debris near the joints.
Getting ready for the visit
- Tell us about access, such as stairs, a lift or high-level joints
- Mention any leaks or damp you’ve noticed
- Keep children and pets away from the work area
Getting a quote
To get a quote, ring 0345 464 0079 or email us and tell us where the job is and what the problem looks like. You’ll have a clear quote before work begins.
Read more
Common questions in Barnet
I let a flat near New Barnet station. Can you help?
Yes, landlords and agents are among the people we work for. Just ring 0345 464 0079 or drop us an email with the address and what needs doing, and we’ll give you a clear price.
Is parking an issue for gutter sealing in Barnet?
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.
Will you clear out my gutters?
The joints we seal are cleaned out and any debris nearby is cleared. A full gutter clean is a separate service.
Can you work on commercial sites?
Yes. We have worked for hotels, offices and other businesses and we are fully insured.
What sealant do you use?
We choose the sealant for the joint, not the other way round. Movement, water and weather all affect the choice, and we’ll explain our choice.
When is the sealant fully cured?
Most sealants are touch-dry well before they’re fully cured. We’ll give you the cure time for the product we used.
Where are you based?
Mr Mastic is based in Crawley. We cover Barnet and the rest of Greater London.
What guarantee comes with the job?
You get our one-year guarantee on every job.
Also in Barnet
What gutter sealing looks like in Barnet
Rainfall in the South East is lower than in much of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day. 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 let a flat or house near New Barnet station, a dripping gutter joint or loose fascia trim is easy to miss until damp shows inside. Managing a site like Grasvenor Avenue Infant School? Then its movement joints, gutters and trims need looking after like any other building’s. If you live in an older home near St John's United Reformed Church, older walls, gutters and the joints where extensions meet them need a flexible sealant.
Barnet is about 9 miles east of Watford, in Greater London. Our applicators cover gutter sealing for homes and businesses in Barnet. 764 places in Greater London are on our list, large and small. Our London page covers work nearby, about 11 miles away.
Here we cover the EN5, EN4, N20 and N11 postcode area for gutter sealing. You will find streets such as Station Road, High Street and Sambroke Square. Main roads around Barnet include the B193 and A1081, so getting to you is simple. Neighbouring places we cover for gutter sealing include Underhill (1 mile west), New Barnet (1 mile east), Monken Hadley (1 mile north-west), Hadley Wood (1 mile north-east) and Cockfosters (1 mile east). Within a short drive, we also cover London (11 miles south), City of Westminster (9 miles south), Marylebone (9 miles south), Kensington (10 miles south), St Pancras (9 miles south) and Shoreditch (10 miles south-east).
Local landmarks in Barnet
We work in homes and buildings around Queen Elizabeth's Girls' School, The Railway Tavern and Highlands Gardens, among other places. The closest station to Barnet is New Barnet station, roughly 0.6 miles east. Other landmarks nearby include Barnet General Hospital (1.2 miles west) and Francis Skaryna Belarusian Library and Museum (2.1 miles south). Open spaces near Barnet include Darland's Lake and Greenhill Gardens.
Why it’s worth doing now in Barnet
Sealing over a dirty, wet joint is a quick fix that rarely lasts, but it soon lets go. Proper preparation is the difference. Converted houses in London often have a bathroom above someone else’s living room, and a slow leak from a failed seal can end up in the flat below. Dealing with it early is far simpler.
Every job is a little different, so we quote each one individually. The number of joints, how easy they are to reach and the sealant needed all make a difference.
Why us?
- We never seal over old sealant
- Experience in homes, commercial sites and hotels
- Sealant colour chosen to suit
- Colour agreed with you before any work starts