East Sussex · England
External Mastic in Lewes
Problem with your movement joints in Lewes? We remove the old material, prepare the joints and seal them properly, and the work is guaranteed for a year.
- Failed seals between different materials
- Rain getting behind render or cladding at a joint
- Weathered mastic that no longer stretches
About our external mastic in Lewes
Getting the depth right is half the job. 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. We work on façade panels, concrete & block and copings & trims, and the jobs we see most are movement joints filled with mortar instead of sealant and panel joints letting water in.
Around Lewes, outside jobs take in garage door frames, porches, gutters and trims as well as walls. Where two materials meet, they move differently, and the sealant has to allow for it.
Our work is backed for twelve months.
- Location
- Lewes (BN7, BN8, BN6, RH15)
- Region
- East Sussex
- Cover
- 12 months on all our work
- Quote
- A clear quote up front
- Call
- 0345 464 0079
- Last updated
- 26 October 2026
Lewes buildings and the weather
With historic houses such as Anne of Cleves House (about 0.6 miles south) nearby, there’s older building stock in the area around Lewes as well as newer homes. In older buildings, older walls and rooflines need a sealant that moves with them and suits the material. The South East is one of the drier parts of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
For site and facilities teams at buildings such as Lewes Old Grammar School, movement joints, cladding joints and gutters on larger buildings need the same care as a house’s. Homes close to Church of St John sub Castro include some older properties, and an extension built onto an older house moves differently, and the joint between them takes the strain.
Lewes is about 7 miles north-east of Brighton, in East Sussex. Whether you’re in the middle of Lewes or further out, we cover external mastic for every kind of property, from flats and houses to offices and hotels. Lewes is one of 289 towns and villages in East Sussex where we work for external mastic. We also work in Brighton, about 7 miles from Lewes.
Here we cover the BN7, BN8, BN6 and RH15 postcode area for external mastic. We cover properties on Market Lane, Market Street and High Street and the roads around them. Main roads around Lewes include the A26 and A275. Nearby, we also carry out external mastic in South Malling (1 mile north-east), Southover (1 mile south-east), Cliffe (1 mile east), Offham (1 mile north-west) and Hamsey (1 mile north). Within a short drive, we also cover Eastbourne (14 miles south-east), Seaford (8 miles south-east), Hailsham (11 miles east), Crowborough (14 miles north-east), Uckfield (8 miles north-east) and Newhaven (6 miles south). Lewes is among the bigger towns we cover in East Sussex.
Local landmarks in Lewes
We work in homes and buildings around Priory School, St Pancras Catholic Primary School and Railway Land, among other places. The closest station to Lewes is Lewes station, about 0.6 miles south-east. Other landmarks nearby include Lewes Victoria Hospital (0.5 miles west) and Museum of Agricultural Bygones (3.9 miles east). Green spaces nearby include Offham Hill and Malling Down.
FAQs for Lewes
What guarantee comes with external mastic in Lewes?
Every job comes with our one-year guarantee, wherever it is. We are also fully insured and ARBOMaster approved.
Can you do external mastic in Lewes?
Yes, Lewes is within the area we cover. We work across London and the South East. You can ring 0345 464 0079 or drop us an email and let us know what needs doing.
Will the old sealant be removed?
Yes. We cut out all the old sealant and clean the joint.
Where are you based?
We’re a Crawley-based firm, with over 20 years’ experience. Our area covers South East England, London and Scotland.
Can you reach joints on upper floors?
It depends on the height and the site. Ground-floor joints are simple; for higher work, tell us about the building and we’ll confirm what’s needed.
Do you do commercial work?
Yes. Commercial and hotel work is a large part of what we do, as well as homes. Working times can be discussed when we quote.
Can you quote for more than one area?
Of course. Doing several areas at once is normally more efficient, so mention them when you ask for a quote.
Can a movement joint be filled with mortar?
No, not where the gap is a movement joint. Pointing it stops it working. We will reseal it with a flexible sealant.
Leave it or put it right?
An open joint keeps letting water into the wall with every downpour. In cold weather, frost can damage wet brick and render, so the problem grows beyond the joint itself. In a family home in Lewes, a failed seal around a bath or a frame lets water into places you can’t see, such as under the floor, behind a panel or into a wall. Whatever the joint, failed sealant only gets worse.
Leaving a failed joint generally makes the job bigger, not smaller, as water and mould keep getting in. If you’re unsure, ring 0345 464 0079 or email us for an honest opinion and a quote.
Why us?
- A sealant colour to suit the surroundings
- White, clear, grey or coloured to suit, where the product allows
- A 12-month guarantee on all work
- 180+ five-star Google reviews
Take a look at our cost guide or our reviews.
DIY versus a professional finish
If you’ve already had a go yourself, that’s fine. We remove it and do the joint properly, so tell us about it when you ask for a quote.
Sealing over old silicone is the commonest DIY error. New silicone won’t bond to old, so it peels away and traps moisture behind it. Everything old must be removed first.
Looking after it afterwards
Joint life depends on how it’s used and looked after. Here’s what we suggest:
- Tell anyone working on the walls about the movement joints
- Get split or bare joints resealed while the damage is small
- Clear growth from the base of walls and joints
- Fix overflowing gutters above sealed joints
Have a quick look at the joints each spring. Watch for splits, edges coming away or growth in the joint.
A joint that has stopped moving pushes the movement elsewhere, often as cracks near the joint. Resealing it early helps prevent that.
Different surfaces, different methods
Copings and trims
Coping and trim joints face rain and sun head on. We reseal them with an exterior sealant suited to the material.
Concrete and blockwork
Big joints in concrete need careful depth control. Backing rod sized to the joint sets it.
What we cannot put right
It helps to know what we cannot do too:
- Damp that is not coming from the joint
- Cutting new joints into brickwork, which is building work rather than sealant work
- Cracked brickwork or render that needs a builder or plasterer
If you’re not sure, just ring 0345 464 0079 or email us and we’ll give you a straight answer before booking.
Where we work in Lewes
- Joints between brick and frames
- Brickwork movement joints
- Render & cladding joints
- Concrete & block
- Façade panels
- Copings & trims
Signs you need external mastic in Lewes
Using the wrong sealant is another common reason. A stiff, general-purpose sealant cannot cope with a joint that moves a lot, and it tears off the sides.
People usually contact us after spotting something like this:
- Leaking joints around cladding and façade panels
- Sealant pulling away from one side of the joint
- Rain getting behind render or cladding at a joint
- Failed seals between different materials
For landlords with property near Lewes station, outside joints that have cracked can let damp into a rental, so check them between lets.
Before booking anyone
- What happens if the job turns out different
- How the joint is cleaned and prepared
- Is the old sealant removed completely?
- How long to leave it before use
How the visit works
You don’t need to clear the whole room or building before we come, only the area right around the joints. We protect the rest, and the job takes a few hours for a handful of joints, longer for a whole elevation in most cases. A visit in Lewes needs access to the work and a place to park close by. If the job is outside, mention gates, side access and anything above ground floor.
- 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.
- The faces are brushed clean and primed where the product requires it.
- Backing rod sized to the joint goes in to set the depth.
- The exterior sealant is applied, tooled and checked along its length.
Getting ready for the visit
- Move anything stored near the joints
- Tell us about access, such as stairs, a lift or high-level joints
- Let us know about parking restrictions
Get a quote
For a quick quote, get us on the phone, or email us if that is easier. Describe what needs sealing and we will explain what’s involved and send you a clear quote.