Hampshire · England
Segensworth External Mastic
We cover Segensworth for sealing brickwork movement joints, render, cladding and façade joints. Old sealant removed completely, joints prepared properly.
- Weeds or debris growing in open joints
- Old sealant gone brittle and cracked
- Joints with sealant missing in places
External mastic in Segensworth
We cut out failed sealant, set the joint depth with closed-cell backing rod and reseal with a low-modulus exterior sealant. We pick a colour that sits well with the wall. If you have cracked joints where brick meets render or frames and joints with sealant missing in places, we can put it right, on brickwork movement joints, façade panels and concrete & block alike.
External sealant needs dry, clean surfaces, so work around Segensworth is planned for dry weather. Let us know about access to every wall, plus any garages or outbuildings.
The work is covered for a year after we finish. If there’s a problem with it, please ring 0345 464 0079 or email us.
- Location
- Segensworth (PO15, SO31)
- Region
- Hampshire
- Guarantee
- 12 months on all our work
- Price
- A clear price before any work starts
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
Do you need external mastic in Segensworth?
Joints sealed without backing rod, or far too deep, rarely last. If the sealant sticks to the back as well as the sides, it cannot stretch and rips as the joint opens.
Look out for these signs:
- Old sealant gone brittle and cracked
- Sealant that has lost its bond to the brick or render
- Water getting into walls through failed joints
- Weeds or debris growing in open joints
For site and facilities teams at buildings such as Cornerstone CofE (VA) Primary School, larger buildings have long runs of movement joint that eventually need resealing.
What to look for in a quote
- What happens if they find a problem under the old sealant
- Is VAT in the price?
- The length of the guarantee
- How much experience the applicator has
Walls and rooflines in Segensworth
Segensworth is within about 3 miles of the coast, where wind-driven rain is a fact of life and, nearer the shore, so is salt air. That’s hard on movement joints and outside wall joints, especially on the side facing the sea. Rainfall in the South East is lower than in much of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
For an older house near a landmark such as St John, an extension built onto an older house moves differently, and the joint between them takes the strain. If you let a flat or house near Swanwick station, failed wall and movement joints let damp in, so they’re worth checking between tenancies.
Segensworth is about 3 miles north-west of Fareham, in Hampshire. Jobs in Segensworth get the same care as everywhere else we work: the old material taken out, joints prepared properly and a 12-month guarantee. Segensworth is one of 683 places in Hampshire where we work for external mastic. You can also see our page for Southampton, about 7 miles away.
Jobs for external mastic in PO15 and SO31 is quoted and booked the same way as anywhere else. External mastic is available to properties on Witherbed Lane, Brunel Way and Concorde Way and the roads around them. Nearby, we also carry out external mastic in Titchfield Park (1 mile south), Park Gate (1 mile west), Locks Heath (1 mile south-west), Whiteley (1 mile north) and Titchfield Common (1 mile south-west). Larger places within reach include Winchester (13 miles north), Gosport (6 miles south-east), Havant (11 miles east), Eastleigh (8 miles north-west), Fareham (3 miles south-east) and Horndean (11 miles east).
Landmarks near Segensworth
Typical jobs here are in homes near The Henry Cort Community College and the streets around them. Segensworth’s nearest station is Swanwick station, about 0.9 miles north-west of the centre. A little further out are Fareham Community Hospital (1.2 miles west) and St Andrew's Castle (3.2 miles west). The countryside around Segensworth includes Swanwick Lakes.
FAQs for Segensworth
Do you cover smaller places like Segensworth?
Yes. Segensworth is within the area we cover, which takes in towns, villages and rural addresses. We work across London and the South East. Let us know about access, parking and anything unusual about getting there when you book.
Is external mastic in a coastal place like Segensworth any different?
Coastal weather is harder on outside sealant: there’s more wind-driven rain and, closer to the shore, salt in the air. The right product, a clean joint and the right depth all help it cope.
Is it OK to fill a movement joint with cement?
No. Rigid materials can’t move with the wall. If it has already been filled, we can usually cut it out and reseal it.
What do you put in the joint?
We choose the sealant for the joint, not the other way round. Where it moves, gets wet or faces the weather makes a difference, and we will tell you what we’re using.
How long should I leave it?
Most sealants are touch-dry well before they’re fully cured. We will give you the cure time for the product we used before we leave.
Is the work guaranteed?
Yes. Each job is guaranteed for twelve months, large or small.
Can you match the colour of my brickwork?
We aim for a joint that suits the wall rather than one that jumps out. We will talk through colour options before any work starts, matched as closely as the range allows.
Do you have insurance?
Yes. Mr Mastic is fully insured.
Nearby places to Segensworth
More services for Segensworth
What we cannot put right
We will always be straight with you, so here’s what sealant cannot fix:
- Cracks in the bricks or render themselves, away from the joints
- Subsidence or other structural problems
- Cutting new joints into brickwork, which is building work rather than sealant work
If you’re not sure, just phone 0345 464 0079 or email us and we will give you a straight answer.
Joints and surfaces we work on
- Façade panels
- Brickwork movement joints
- Render & cladding joints
- Concrete & block
- Copings & trims
- Joints between brick and frames
The process
Most of a good job is in the 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 to a few days, depending on the length of joint and the access. Somewhere as small as Segensworth, access is often the only tricky part. For outside work, also let us know about exposed walls and any outbuildings involved.
- We look at every joint and agree a colour to suit the wall.
- We take out the old sealant until the faces are sound.
- Closed-cell backing rod is pushed in so the sealant bonds to two sides only.
- We prime the faces where required.
- We gun in low-modulus sealant and tool it neatly.
Before we arrive
- Tell us about any previous sealing or DIY attempts
- Tell us about any water getting in
- For indoor joints, keep the area dry beforehand if you can
Ask for a quote
Getting a quote is simple: let us know the job and the location and its rough size. A few photos by email make the job easier to understand.
Read more
Can I do it myself?
Not every job suits DIY: work at height, external movement joints, fire-rated sealant and large areas need the right product, the right access and the right method.
Overfilling a joint is a classic DIY mistake. A thick, smeared bead looks untidy and does not move well, and the joint depth matters as much as the finish.
Aftercare tips
How long the joints last depends on use and care. Here’s what we suggest:
- Wash walls gently around the sealant
- Point out the joints to other trades
- Ask before painting over external sealant
- Keep movement joints as flexible joints, not mortar
Only paint over the joint if we have confirmed the sealant can take paint. Many exterior sealants are not designed to be painted, and paint can crack as the joint moves.
Once a joint can’t move, the wall finds another way, usually as cracking in the brickwork or render nearby. Catch it early and you reduce the risk.
Surface by surface
Copings and trims
Coping joints that leak let water straight down into the wall. Resealing them is a small job that protects a lot.
Render joints
Water behind render can lead to blown patches. A sound joint keeps the render dry behind.
For landlords and businesses
Housing providers, facilities teams and property managers book us too in Segensworth and across Hampshire. We can quote a run of properties together, and we’re fully insured for the work.
Businesses can book us for washrooms, kitchens, offices and more. For commercial premises, we can talk through working times when we quote.