Hampshire · England
Cowplain External Mastic
Sealing brickwork movement joints, render, cladding and façade joints for Cowplain, backed by a one-year guarantee. Call for a quick quote.
- Joints with sealant missing in places
- Joints pointed up with cement by mistake
- Sealant that has lost its bond to the brick or render
External mastic for homes and businesses in Cowplain
We are ARBOMaster approved applicators, and each external joint gets a sealant suited to it. Some surfaces need a primer before sealing. We work on brickwork movement joints, render & cladding joints and copings & trims, and the jobs we see most are joints where the bead has come unstuck and weeds or debris growing in open joints.
Houses in smaller places like Cowplain can stand more in the open than those in a built-up town, and walls and rooflines facing the weather take the worst of it. That is where gutter joints and wall joints tend to fail first.
You get a one-year guarantee, the same in Cowplain as everywhere else we work.
- Location
- Cowplain (PO8, PO7)
- Wider area
- Hampshire
- Guarantee
- One year on every job
- Price
- Quoted before any work starts
- Call
- 0345 464 0079
- Last updated
- 26 October 2026
How we quote for external mastic
Your quote is based on your job. We take into account:
- The number and length of the joints
- When we can work, for business premises
- Access and height
- Whether there’s mould to deal with
Commercial jobs are quoted on the same basis as homes: the amount of work, the access and the products needed. Call for a quick quote and we’ll go through it with you.
What we need to know
Photos help, but a description is a good start. Try to tell us:
- Whether it has been sealed before
- Access, such as stairs, a lift or height
- How many joints, rooms or windows are involved
- Whether it’s a home or a business
There’s no standard price list, as no two jobs are quite the same. Instead, we send you a clear quote for your job. To arrange one, phone 0345 464 0079 or email us.
How it works
All our tools and materials come with us in the van, so there’s nothing for you to buy. Once we’ve agreed what’s being done, we protect the area and start. Most jobs take anything from a few hours to several days, depending on the building. Parking around Cowplain is usually easier than in a town centre, but mention any lanes, gates or long drives. If the job is outside, tell us about side access and how high the joints are.
- We start by checking each joint, agreeing the ones to redo and how we will reach them.
- We cut out the failed sealant and rake out any dirt or growth.
- Both sides are cleaned back to sound material and primed if needed.
- 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.
Preparing for the visit
- Mention any sign-in or site rules at work premises
- Plan for the work area to be out of bounds to pets and children
- Mention any leaks or damp you’ve noticed
How to get a quote
For a quote, phone 0345 464 0079 or send us an email with the location and a short description of the problem. You’ll have a clear quote before any work starts.
Advice
How the job changes by surface
Copings and trims
Metal and stone copings both move with temperature, so a flexible sealant suits them best in all weathers.
Joints between dissimilar materials
Where a frame or panel meets masonry, water often finds a way in. The old joint is removed and a sealant that bonds to both sides goes in.
Walls and rooflines in Cowplain
London and the South East are among the drier parts of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day. With historic houses such as Warblington Castle (about 4.5 miles south-east) nearby, there’s older building stock in the area around Cowplain as well as newer homes. In older buildings, older brick and stone need a sealant that suits them, at the right joint depth.
Letting a property close to Rowlands Castle station? Then split movement joints are easy to miss on a rental until damp shows inside. Managing a site like Woodcroft Primary? Then its movement joints, gutters and trims need looking after like any other building’s. Homes close to The Hart Plain Church include some older properties, and an extension built onto an older house moves differently, and the joint between them takes the strain.
Cowplain is about 1 mile south-west of Horndean, in Hampshire. We provide external mastic to homes and businesses in Cowplain and nearby, as part of our work across Hampshire. Our Hampshire coverage runs to 683 places, Cowplain among them. You can also see our page for Portsmouth, about 7 miles away.
Work in PO8 and PO7 is quoted and booked the same way as anywhere else. That includes homes and businesses on Milton Road, King's Road and London Road and the roads around them. Other places close to Cowplain include Hart Plain (1 mile south-west), Waterlooville (1 mile south), Soake (1 mile west), Furzeley Corner (2 miles west) and Purbrook (2 miles south). We also work in nearby towns such as Gosport (9 miles south-west), Havant (3 miles south-east), Eastleigh (15 miles west), Fareham (8 miles south-west), Hedge End (12 miles west) and Petersfield (8 miles north-east).
What’s near Cowplain
Around Cowplain, our work takes us to homes and buildings near The Cowplain School. Cowplain’s nearest station is Rowlands Castle station, roughly 3 miles east. Nearby you will also find Havant Museum (3.9 miles south-east) and Havant War Memorial Hospital (3.5 miles south-east). Not far away are Windmill Hill and Southmoor Nature Reserve.
Looking after it afterwards
A little care helps the new joints last. We recommend:
- Have failed joints looked at early
- Make sure movement joints are not pointed over
- Clear growth from the base of walls and joints
- Avoid pressure-washing directly into sealant joints
Make sure anyone working on the wall later knows where the movement joints are. They must stay as flexible joints, never rendered or pointed over.
Leave a failed movement joint and water keeps getting into the wall. That can lead to damp patches, staining and frost damage.
When it isn’t the sealant
Some problems need a builder, plumber or other trade rather than us:
- Cracking across the wall rather than at a joint
- Rising or penetrating damp from elsewhere in the wall
- Structural movement, which needs a surveyor or engineer
Not sure which it is? You can ring 0345 464 0079 or email us and we’ll tell you honestly before booking.
Joints and surfaces we work on
- Copings & trims
- Joints between brick and frames
- Brickwork movement joints
- Render & cladding joints
- Façade panels
- Concrete & block
What happens if it’s left?
A properly done movement joint is an even line in a colour that suits the wall. A rushed bead with no backing looks untidy and doesn’t last, so it pays to do it properly once. Homes in smaller places like Cowplain can face more weather, and failed outside joints let damp into walls. Indoors, a failed seal lets water into floors and panels as it would anywhere.
There are no prices on our website, because each job is priced on what it involves. For a quick quote, please call 0345 464 0079 or send us an email and we will talk you through it.
What you get with us
- A 12-month guarantee on all work
- Quality sealants from Arbo and Everbuild
- Anti-fungal sanitary silicone in wet areas
- Full insurance on every job
Take a look at what affects the cost and our reviews.
Questions from Cowplain
Is Cowplain within the area you cover?
Yes, Cowplain is covered. We work across London and the South East, from towns to the smallest places. The journey is planned ahead, so it helps to know about access.
Do you cover Cowplain for external mastic?
Yes. We work across London and the South East, and Cowplain is part of that. Just ring 0345 464 0079 or send us an email with a few details of the job.
Do you hold any approvals?
Yes. We’re approved under the ARBOMaster scheme, which is run for the Arbo sealant brand.
Will you leave a mess?
No. We work neatly, protect the area around the joints and tidy up afterwards.
Should I point up the gap in my brickwork?
No, not if it’s a movement joint. Filling it with mortar defeats its purpose. A flexible sealant is the right fill.
Can you seal joints between render and window frames?
Yes. The old joint is removed, both surfaces cleaned and primed where needed, and a flexible sealant applied. We pick a colour that works with both materials.
How long before the joint can be used?
That depends on the sealant used, so please follow the time we give you when we finish.
I’m a tenant. Can you help?
Of course. Ask your landlord first, and we can send them the quote if that helps.
DIY sealant or a professional job?
The biggest DIY mistake is sealing over old sealant. Silicone doesn’t stick to old silicone, so it lifts and traps water and mould underneath. Everything old must be removed first.
A DIY attempt does not rule out a professional job. We cut it out and start again.