Hampshire · England
External & façade joints in Blacknest, Hampshire
Sealing brickwork movement joints, render, cladding and façade joints for householders, landlords and businesses in Blacknest. ARBOMaster approved applicators, fully insured, with a one-year guarantee.
- Rain getting behind render or cladding at a joint
- Old sealant gone brittle and cracked
- Moss and dirt in joints with no sealant left
External mastic in Blacknest
Movement joints let brickwork, render and cladding expand and shrink without cracking. Its sealant has to flex with the building, season after season, and when it fails, the wall takes the strain and water finds a way in. If you have moss and dirt in joints with no sealant left and weathered mastic that no longer stretches, we can help, on render & cladding joints, concrete & block and joints between brick and frames alike.
External sealant needs dry, clean surfaces, so work around Blacknest is planned for dry weather. Let us know about access to every wall, plus any garages or outbuildings.
The work is guaranteed for twelve months. If there’s a problem with our work within the year, let us know and we’ll sort it.
- Location
- Blacknest (GU34)
- Wider area
- Hampshire
- Guarantee
- A year, on every job
- Price
- A clear price before we start
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
Surface by surface
Copings and trims
Joints in copings, parapets and trims are exposed to the worst of the weather. Each is resealed with a weatherproof, flexible sealant.
Joints between dissimilar materials
Wherever two materials meet, they move differently. We seal the joint with a flexible exterior sealant so neither cracks the other.
Towns and villages near Blacknest
Also in Blacknest
Your questions about external mastic in Blacknest
Can you help a landlord with a rental near Bentley (Hampshire) station?
Yes, rental work is part of what we do. You can phone 0345 464 0079 or drop us an email with the address and a few details, and we will give you a fixed price before work begins.
Will you come out to Blacknest?
Yes, smaller places are covered as well as towns. We work across London and the South East. Let us know about access, parking and anything unusual about getting there when you book.
Do you hold any approvals?
Yes. We’re an ARBOMaster approved applicator.
Can you seal joints between render and window frames?
Yes. Different materials move at different rates, so the joint between them must be flexible. The sealant is matched to both sides.
Are you insured?
Yes. Mr Mastic is fully insured, with over 20 years’ experience in sealant work.
When will the joints need doing again?
There’s no fixed answer: sunny, exposed elevations and busy joints wear faster. A yearly look will tell you when they need doing. Our work comes with a 12-month guarantee.
Does someone need to be in?
If the work is inside, we need someone to let us in. Once we’ve agreed the job, you do not need to watch us work.
Will you leave a mess?
Tidy work is part of the job. Nearby surfaces are protected, and we clear up when we’re done.
Aftercare tips
Simple care keeps the joints in good condition. Our advice:
- Avoid pressure-washing directly into sealant joints
- Ask before painting over external sealant
- Get split or bare joints resealed while the damage is small
- Deal with leaking gutters that soak the joints below
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.
Gaps, plants or missing sealant in a joint are worth getting looked at. Earlier resealing means a smaller job and a better result.
Why deal with it now?
Running new sealant over the old bead rarely lasts. The new layer can’t bond properly to old, weathered material, so we always take the old sealant out. In a small place like Blacknest, homes can be exposed to wind and rain, which finds any gap, and damp in older walls is slow to dry out.
Rather than a set price list, we price the job in front of us: how many joints, what’s in them now and how we reach them. You will know the price before we begin.
Why us?
- An ARBOMaster approved applicator
- More than 20 years in sealant work
- Trusted Arbo and Everbuild sealants
- A 12-month guarantee on all work
Take a look at our cost guide or our reviews.
Landlord and commercial work in Blacknest
We work for landlords and agents as well as homeowners. Resealing between tenancies keeps a property looking cared for before the next move-in.
Whether it’s one flat or a portfolio, you get the same standard of work: the old material taken out, careful preparation and a 12-month guarantee.
What affects the quote in Blacknest
We quote each job individually. This is what makes a difference:
- The type of sealant required
- Mould in or behind the old joints
- When we can work, for business premises
- Whether the work is at height
The cost reflects the work involved, not guesswork. That is why we ask about the job first.
Helping us quote
Photos help, but a description is a good start. Try to tell us:
- What the problem is, such as mould, gaps, leaks or cracking
- The address or postcode of the job
- How many joints, rooms or windows are involved
- Access, such as stairs, a lift or height
Getting a quote is simple: tell us what needs doing and where. Photos by email help us understand the job, and we will take it from there.
What we do, step by step
Once we are on site, we check the joints match what you told us. If we find something unexpected, we talk it through with you first. Most jobs then take anything from a few hours to several days, depending on the building. For a village or hamlet like Blacknest, the journey is planned in advance: let us know about lanes, gates and parking. We bring what the job needs, so it can be finished in one trip where possible.
- We look at every joint and agree a colour to suit the wall.
- Failed sealant is removed back to clean, sound faces.
- 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
- For business premises, tell us about site rules or sign-in
- Mention any leaks or damp you’ve noticed
- Mention any tricky access
How to get a quote
For a quote, call 0345 464 0079 or email us with the location and a short description of the problem. You’ll have a clear quote before work begins.
Read more
What external mastic looks like in Blacknest
Compared with the north and west, the South East gets less rain, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day. With historic houses such as Farnham Castle (about 4.1 miles north-east) nearby, there’s older building stock in the area around Blacknest as well as newer homes. In older buildings, older walls and rooflines need a sealant that moves with them and suits the material.
Historic houses such as Farnham Castle, about 4.1 miles north-east, show how far back building around Blacknest goes.
Blacknest is about 4 miles south-west of Farnham, in Hampshire. Across the GU34 area, we can carry out external mastic at your property. Blacknest is one of 683 towns and villages in Hampshire we cover for external mastic. Reading is on our list too, around 20 miles away.
All of GU34 is within our area for external mastic, from the main roads to the quietest streets. Neighbouring places we cover for external mastic include Bucks Horn Oak (1 mile east), Isington (1 mile west), Bentley (1 mile north-west), Binsted (1 mile south-west) and Frithend (1 mile south-east). We also work in nearby towns such as Basingstoke (12 miles north-west), Farnborough (9 miles north-east), Fleet (7 miles north), Aldershot (7 miles north-east), Alton (5 miles west) and Petersfield (12 miles south).
Landmarks near Blacknest
Locally, jobs take us to homes and businesses close to The Jolly Farmer pub, among other places. For rail, the closest station is Bentley (Hampshire) station, about 0.5 miles north of the centre. Nearby you will also find Chase Community Hospital (4.7 miles south) and Barley Pound (2.7 miles north). For a walk, there’s Holybourne Hill and Farnham Heath.
When to call us in Blacknest
Some movement joints have been pointed up with mortar, often by someone who didn’t know what it was for. With the joint locked solid, the movement turns into cracks elsewhere in the wall.
Common reasons people contact us include:
- Failed seals between different materials
- Brick movement joints where the sealant has split
- Leaking joints around cladding and façade panels
- Moss and dirt in joints with no sealant left
For landlords with property near Bentley (Hampshire) station, outside joints that have cracked can let damp into a rental, so check them between lets.
What to look for in a quote
- Whether all the old sealant comes out first
- Whether you can choose the colour
- What the quote includes, VAT included or not
- What insurance they hold