Hampshire · England
External Mastic in Hart Plain
Movement joints in Hart Plain need attention? We remove the old material, prepare the joints and seal them properly.
- Leaking joints around cladding and façade panels
- Water getting into walls through failed joints
- Plants rooting in failed movement joints
External mastic in Hart Plain
Where two different materials meet, such as brick and render or blockwork and metal, they move at different rates. A flexible exterior sealant takes up that movement where mortar or filler would crack. Typical jobs include movement joints filled with mortar instead of sealant and leaking joints around cladding and façade panels, across copings & trims, brickwork movement joints and façade panels.
Around Hart Plain, garages, outbuildings and extensions all add to the joints on the outside of a home. Gutter ends, garage door frames and the joints where an extension meets the house are typical spots for leaks.
We stand behind the work with a one-year guarantee, so you are not left on your own once the job is done.
- Place
- Hart Plain (PO8, PO7)
- Region
- Hampshire
- Cover
- One year on every job
- Quote
- A clear price before work begins
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
When something else is needed
New sealant cannot fix everything, and we will tell you before any work starts. It will not solve:
- Movement that’s more than a sealant joint can take
- Cracked brickwork or render that needs a builder or plasterer
- Loose or hollow render, which needs re-rendering
If in doubt, call 0345 464 0079 or email us and we’ll say what we think.
Surfaces we seal
- Façade panels
- Render & cladding joints
- Copings & trims
- Concrete & block
- Joints between brick and frames
- Brickwork movement joints
Signs you need external mastic in Hart Plain
If plants are growing out of a joint, the sealant has usually failed or was never there. Roots and dirt hold water against the wall and make things worse.
Signs it’s time to call us include:
- Failed sealant between panels on a façade
- Joints with sealant missing in places
- Sealant that has lost its bond to the brick or render
- Damp patches traced to an open external joint
In the older streets around The Hart Plain Church, older walls, gutters and the joints where extensions meet them need a flexible sealant.
Questions to ask before booking
- What the cure time is
- Is the old sealant removed completely?
- What guarantee comes with the work
- How much experience the applicator has
Towns and villages near Hart Plain
Also in Hart Plain
Walls and rooflines in Hart Plain
Historic houses like Warblington Castle (about 4.5 miles south-east) are a reminder that the area around Hart Plain has older buildings as well as new. Where a home is older, older brick and stone need a sealant that suits them, at the right joint depth. 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 site and facilities teams at buildings such as Hart Plain Infant School, larger buildings have long runs of movement joint that eventually need resealing. Letting a property close to Rowlands Castle station? Then failed wall and movement joints let damp in, so they’re worth checking between tenancies.
Hart Plain is about 1 mile north of Waterlooville, in Hampshire. For external mastic in and around Hart Plain, it’s easy to get a quote: please phone 0345 464 0079 or email us. We cover Hampshire from our Crawley base. Across Hampshire, we cover 683 places, and Hart Plain is one of them. We also work in Portsmouth, about 6 miles from Hart Plain.
Our applicators cover all of the PO8 and PO7 postcode area for external mastic and the streets around it. External mastic is available to properties on Milton Road, King's Road and Eagle Avenue. We also cover Cowplain (1 mile north-east), 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 (8 miles south-west), Havant (3 miles south-east), Eastleigh (15 miles west), Fareham (8 miles south-west), Hedge End (12 miles west) and Petersfield (9 miles north-east).
What’s near Hart Plain
Locally, jobs take us to homes and businesses close to The Cowplain School. For rail, the closest station is Rowlands Castle station, about 3.1 miles east of the centre. Well-known places in the area include Havant Museum (3.9 miles south-east) and Clanfield Earthwork (4.1 miles north-east). For a walk, there’s Southmoor Nature Reserve and Windmill Hill.
Landlords, agents and businesses in Hart Plain
For anyone letting property in or around Hart Plain, jobs at different addresses can be quoted together. Just tell us the addresses and what each one needs.
Letting agents often deal with us directly. Tell us the address, the job and how access works.
What affects the quote in Hart Plain
Your quote is based on your job. We look at:
- How many rooms, windows or areas are involved
- The number and length of the joints
- Which sealant suits the joint
- Whether old sealant or filler has to be cut out
Instead of a standard rate, we price the job in front of us: the amount of work, the old material and the access. The price is agreed before we begin.
Asking for a quote
What to tell us when you ask for a quote:
- What’s wrong with the joints now
- How many joints, rooms or windows are involved
- Where the job is, and your postcode
- Whether it’s a home or a business
A good description makes for an accurate quote. Tell us where the job is, what’s wrong and how much there is, and add photos by email if you can.
The process
There isn’t much for you to do on the day. Show us the job and we’ll take it from there. The job generally takes anything from a few hours to several days, depending on the building from start to finish. A visit to Hart Plain is planned like any other: the time, the access and where to park are agreed in advance. Outdoor jobs depend on a dry day, since sealant needs a dry surface.
- Each joint is checked and the colour of the new sealant agreed.
- We take out the old sealant until the faces are sound.
- Backing rod goes in so the sealant can stretch between the two faces.
- Primer is applied wherever the sealant needs it.
- We gun in low-modulus sealant and tool it neatly.
Before we arrive
- Plan for the work area to be out of bounds to pets and children
- Tell us about any water getting in
- Where the joints are inside, avoid wetting them before we arrive
Getting a quote
For a quote, ring 0345 464 0079 or send us an email and tell us where the job is and what the problem looks like. We’ll give you a clear quote before any work starts.
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Your questions about external mastic in Hart Plain
Can you help a landlord with a rental near Rowlands Castle station?
Yes, we work for landlords and agents. You can call 0345 464 0079 or email us with the address and a few details, and we will give you a fixed price before any work starts.
Is Hart Plain within the area you cover?
Yes, Hart Plain is covered. Our work covers London and the South East, from towns to the smallest places. Longer journeys are simply planned in advance.
How do I get a quote for external mastic in Hart Plain?
It depends on the job, so we quote each one individually. For a quick quote, phone 0345 464 0079 or send us an email with a short description of the job.
What is backing rod for?
We fit closed-cell backing rod wherever the joint depth needs controlling. It sets the sealant depth and prevents three-sided bonding so the bead can stretch.
What should I tell you?
Only a few details: the address or postcode, what’s wrong and any access issues. After that, simply ring 0345 464 0079 or send us an email.
Are you an approved applicator?
Yes. Mr Mastic is an ARBOMaster approved applicator and we are fully insured too.
Where is Mr Mastic based?
We work from Crawley. Our applicators cover Hart Plain.
Which products do you use?
It depends on the joint: sanitary silicone where it gets wet, and sealants suited to movement or weather elsewhere. Brands we use include Arbo and Everbuild.
Can I do it myself?
Some jobs are best left to a professional: work at height, external movement joints, fire-rated sealant and large areas need the right product, the right access and the right method.
Too much sealant is as bad as too little. A thick, smeared bead looks untidy and does not move well, and the joint depth matters as much as the finish.
Looking after it afterwards
Once the sealant has cured, a few habits help it last:
- Keep water from gutters off the wall
- Wash walls gently around the sealant
- Ask before painting over external sealant
- Don’t let climbing plants root in the sealant
Keep pressure washers away from the sealant. High-pressure water can lift the edges.
Leaks behind façade panels and render often go unseen. By the time there’s a damp patch, the damage can be well established.