Portsmouth · England
Wymering External Mastic
Specialist external mastic for Wymering: careful preparation, the right product and tidy work. Ask us for a quick quote.
- Joints pointed up with cement by mistake
- Panel joints letting water in
- Brick movement joints where the sealant has split
What the job involves on each surface
Cladding and façade panels
Panels heat up and cool down quickly, so the joint sealant has to cope with frequent movement. The sealant is chosen with that in mind.
Render joints
Water behind render can lead to blown patches. A sound joint keeps the render dry behind.
External mastic in Wymering
On houses, flats and commercial buildings across Wymering, we reseal joints in brickwork, render, cladding and façade panels. The preparation is the same whatever the wall: clean, sound faces and a controlled depth. We work on joints between brick and frames, façade panels and copings & trims, and common reasons people get in touch are rigid filler in a joint that should flex and sealant pulling away from one side of the joint.
Outbuildings, garages and conservatories around homes in places like Wymering add more joints to look after. Leaks usually start at a gutter end, a garage door frame or where an extension meets the house.
You’re covered for a year from the day we finish. If anything isn’t right with it, ring 0345 464 0079 or email us.
- Location
- Wymering (PO6, PO2)
- Wider area
- Portsmouth
- Cover
- A year, on every job
- Price
- A clear price before work begins
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
Wymering buildings and the weather
Wymering is within about 1 mile of the coast, and homes near the sea take more wind-driven rain, with salt in the air closer to the shore. 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, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
For an older house near a landmark such as Church of St Peter and St Paul, an extension built onto an older house moves differently, and the joint between them takes the strain. Letting a property close to Cosham station? Then outside joints that have cracked can let damp into a rental, so check them between lets.
Wymering is about 3 miles north of Portsmouth, in Portsmouth. Homes, rented property, offices and hotels in Wymering is covered for external mastic, old or new, large or small. Every job comes with our one-year guarantee. Our area takes in 19 places across Portsmouth, large and small.
Jobs for external mastic in PO6 and PO2 is quoted and booked the same way as anywhere else. If you need external mastic at a property on Dean Road, Deal Road and Park Lane or a nearby road, we can help. Main roads around Wymering include the A397, so getting to you is simple. We also cover the places around Wymering: Cosham (1 mile south-east), Paulsgrove (1 mile west), Hilsea (1 mile south), Drayton (1 mile east) and Widley (1 mile north-east). We also work in nearby towns such as Portsmouth (3 miles south), Southsea (4 miles south), Milton (4 miles south), Landport (3 miles south), Baffins (3 miles south) and Portsea (4 miles south-west).
Local landmarks in Wymering
Locally, jobs take us to homes and businesses close to Springfield School, UTC Portsmouth and Alexandra Park, among other places. There’s a railway station in Wymering itself: Cosham station. Other landmarks nearby include World War I Remembrance Centre (1.4 miles south-east) and Tricorn Centre (3.1 miles south). The countryside around Wymering includes Portsdown Hill and Southmoor Nature Reserve.
What we’re called out for in Wymering
If plants are growing out of a joint, the sealant has generally failed or was never there. Dirt and roots then trap moisture in the joint and speed up the damage.
Most people get in touch when they notice something like this:
- Movement joints filled with mortar instead of sealant
- Hard, crazed mastic that has stopped moving
- Moss and dirt in joints with no sealant left
- Rain getting behind render or cladding at a joint
For site and facilities teams at buildings such as Medina Primary School, its movement joints, gutters and trims need looking after like any other building’s.
Comparing quotes
- Whether the sealant suits the joint
- What insurance they hold
- How much experience the applicator has
- Which colour the sealant will be
What we do, step by step
There’s no need to move everything out before we come, only the area right around the joints. Everything nearby is protected, and the job takes anything from a few hours to several days, depending on the building in most cases. Parking around Wymering is normally easier than in a town centre, but mention any lanes, gates or long drives. For outside work, side access and the height of the joints help us plan.
- We inspect the joints and agree which need resealing and how they’ll be reached.
- The old mastic and anything lodged in the joint is removed.
- We clean both faces of the joint and prime them where the product calls for it.
- Closed-cell backing rod is fitted to set the depth and stop three-sided bonding.
- We gun in a flexible exterior sealant in a colour that suits the wall and tool it neatly.
Getting ready for the visit
- For business premises, tell us about site rules or sign-in
- Keep children and pets away from the work area
- Move anything stored near the joints
Get a quote
Getting a quote is simple: let us know the job and the location, and roughly how big it is. A few photos by email make the job easier to understand.
Advice
Looking after it afterwards
To keep the joints looking good and working properly:
- Tell anyone working on the walls about the movement joints
- Act on the first splits you see
- Keep soil, plants and ivy away from the joints
- Fix overflowing gutters above sealed joints
Do not paint over the new sealant unless we’ve said the product is paintable. Many exterior sealants are not designed to be painted and spoil the finish.
Water getting behind cladding or render can go unnoticed for a long time. By the time there’s a damp patch, the damage can be well established.
When it isn’t the sealant
New sealant cannot fix everything, and we’d rather say so up front. Sealant won’t put right:
- Movement that is more than a sealant joint can take
- Cracks in the bricks or render themselves, away from the joints
- Damp from another source, such as a leaking gutter or a bridged damp-proof course
If you are not sure, just call 0345 464 0079 or drop us an email and we will give you a straight answer.
Joints and surfaces we work on
- Concrete & block
- Render & cladding joints
- Façade panels
- Joints between brick and frames
- Brickwork movement joints
- Copings & trims
Questions from Wymering
Will you come out to Wymering?
Yes, we do. Our work covers London and the South East, and smaller places are part of that. Longer journeys are simply planned in advance.
Does the coastal weather in Wymering affect outside sealant?
Coastal weather is harder on outside sealant: there’s more wind-driven rain and, closer to the shore, salt in the air. Choosing the right sealant for the frame and wall, laid at the right depth, helps it last.
Why do you put foam in the joint first?
Backing rod goes into deeper joints as a matter of course. It controls the depth and stops the sealant bonding to the back so the bead can stretch.
Will there be a smell?
Some sealants have a smell while they cure, but it fades. Opening a window helps.
Can I do it myself?
That depends on the joint. Work at height, movement joints, fire-rated gaps and large areas are best left to a professional, while a short indoor joint may be within reach.
Can landlords and businesses book you?
Yes. As well as householders, we work for landlords, agents, businesses and hotels in Wymering.
How long will you be here?
A typical job takes anything from a few hours to several days, depending on the building. We’ll confirm how long when we quote.
Can you quote for more than one area?
Yes. Tell us about everything you’d like done.
Should I try it myself first?
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.
If you do try it yourself, take your time over the preparation: remove every trace of old sealant, clean and dry the joint, and follow the product’s cure time. If it fails, we can still redo it.
For landlords and businesses
In hotels, rooms out of use cost money, so we plan the work room by room. We have worked in hotels as well as homes and businesses.
Water getting past a failed joint can damage the building, which matters even more when someone else lives there. Resealing at the right time is simple maintenance that we can handle for you.