Portsmouth · England
New Build Mastic in Cosham
Plot mastic for developers and snagging failed sealant in new homes for homeowners, landlords and businesses in Cosham. Fully insured, ARBOMaster approved and guaranteed for a year.
- Gaps behind new kitchen upstands
- Plot mastic for developers ahead of handover
- Smeared, uneven beads picked up at snagging
What we can’t put right
We’d rather tell you now than do work that won’t last, so these are the limits:
- Structural cracks in walls or ceilings
- Plumbing faults behind the sealant
- Your warranty claim itself, which is between you and the builder
If in doubt, phone 0345 464 0079 or drop us an email and we’ll say what we think before you book.
Surfaces we seal
- Skirting & floors
- Kitchens
- Show homes
- Bathrooms & en suites
- Windows & doors
- Plot handovers
New build mastic in Cosham, done properly
We work in new homes and on new-build sites across Cosham. One shower or a whole phase of plots, the method does not change: remove, clean, prime where needed, then a neat new bead. We are often asked to deal with gaps opening as the house dries out and settles and skirting joints opening in the first winter, across plot handovers, skirting & floors and show homes.
If you’ve bought a new home in or near Cosham, the first year or two is a good time to check the sealant. Gaps at skirtings, shower seals pulling away and missing mastic around frames are common snags.
Whatever the size of the job, you get the same one-year guarantee in Cosham and across Portsmouth.
- Where
- Cosham (PO6, PO3, PO2)
- Region
- Portsmouth
- Guarantee
- One year on every job
- Quote
- A clear price before we start
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
Also near Cosham
Other services in Cosham
Keeping the joints in good condition
To keep the joints looking good and working properly:
- Report sealant problems to your builder during the snagging period
- Look at the sealant regularly in the first couple of years
- Wipe joints with warm soapy water
- Don’t seal over failed sealant yourself
Photograph failed sealant before it’s redone and keep the builder’s replies. It’s useful if you need to raise other issues later.
Report failed sealant to the builder while you’re in the snagging period. Once it ends, the repair may be down to you so report it promptly.
DIY sealant or a professional job?
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.
The biggest DIY mistake is sealing over old sealant. New silicone will not bond to old, so it peels away and traps moisture behind it. Everything old must be removed first.
Your questions about new build mastic in Cosham
Will you come out to Cosham?
Yes, Cosham is covered. Our work covers 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 work for landlords with property near Cosham station?
Yes, landlords and agents are among the people we work for. Just phone 0345 464 0079 or email us with the address and what needs doing, and we will give you a clear quote.
Should I wait before resealing?
Where water is getting through, don’t wait. Small gaps that are just cosmetic can be resealed once movement has slowed.
Will you leave a mess?
Tidy work is part of the job. Nearby surfaces are protected, and we clear up when we are done.
Why does sealant fail so quickly in new builds?
It’s common, and there are normally two reasons: the house moving as it dries, and sealant that never bonded properly. Cutting it out and resealing properly fixes both.
Are you an approved applicator?
Yes. We are an ARBOMaster approved applicator, the approved applicator scheme for Arbo sealants.
Do I need to be at home?
If the work is inside, we need someone to let us in. After that, you can carry on with your day.
Do you guarantee your work?
Yes. Every job comes with a one-year guarantee.
Landlords, agents and businesses in Cosham
We regularly work with letting and managing agents. Tell us the address, the job and how access works.
If you manage several properties in or around Cosham, jobs at different addresses can be quoted together. Just tell us the addresses and what each one needs.
What affects the quote in Cosham
There’s no set price list, because jobs vary so much. What we look at:
- How many rooms, windows or areas are involved
- Whether there’s mould to deal with
- When we can work, for business premises
- How much old sealant there is and how hard it is to remove
There are no prices on our website, because the cost depends so much on the job itself. For a quick quote, please phone 0345 464 0079 or send us an email and we will talk you through it.
What we need to know
A few details help us give you an accurate quote. When you get in contact, it helps to mention:
- Where the job is, and your postcode
- How many joints, rooms or windows are involved
- Pictures of the joints, sent by email
- The problem you’ve noticed
There’s no standard price list. Instead, your job gets its own clear quote. To arrange one, ring 0345 464 0079 or send us an email.
New homes and floors in Cosham
Cosham is within about 1 mile of the coast. Plot mastic on new homes near the coast takes more weather than it would inland, so any gaps are best picked up early. 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.
In and around Cosham, as anywhere, good new build mastic starts with a clean, dry, properly prepared joint. For new homes near Cosham station, it’s worth checking the sealant early, while snags are still fresh.
Cosham is about 2 miles south-west of Purbrook, in Portsmouth. Jobs in Cosham get the same care as everywhere else we work: the old material taken out, joints prepared properly and a 12-month guarantee. Across Portsmouth, we cover 19 places, and Cosham is one of them.
Jobs for new build mastic in PO6, PO3 and PO2 works the same way as everywhere else we cover. Whether your property is on Dean Road, Park Lane and Elgin Road or anywhere close by, our applicators can take on the job. You will find Cosham on the A397, which makes it straightforward to reach. Close by, we work in Wymering (1 mile north-west), Hilsea (1 mile south), Drayton (1 mile east), Widley (1 mile north-east) and Paulsgrove (1 mile west). Within a short drive, we also cover Southsea (4 miles south), Milton (3 miles south), Landport (3 miles south), Portsea (3 miles south-west), Portsmouth Point (4 miles south-west) and Fratton (3 miles south).
Landmarks near Cosham
Typical jobs here are in homes near The First Post pub, Alexandra Park and Springfield School. Cosham has its own railway station: Cosham station. Well-known places in the area include Tricorn Centre (2.9 miles south) and World War I Remembrance Centre (1 mile south-east). Open spaces near Cosham include Southmoor Nature Reserve and Portsdown Hill.
How it works
There’s no need to move everything out, only the area right around the joints. Everything nearby is protected, and the work takes anything from a few hours to several days, depending on the number of plots for a typical job. Parking around Cosham is usually 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.
- First, the list of joints is agreed from your snagging sheet or plot schedule.
- The failed sealant is removed completely down to clean surfaces.
- We clean out the dust and grit left from the build.
- We prime where needed and apply a sealant suited to each joint.
- We tool every joint neatly and tell you when each area can be used.
Getting ready for the visit
- Try not to wet indoor joints just before the visit
- Move anything stored near the joints
- Tell us about any water getting in
How to get a quote
To get a quote, ring 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.
Related advice
Why act early in Cosham
Resealing everything on a snagging list in one visit is normally simpler than chasing joints one at a time. It’s one visit, one quote and one set of cure times to plan around. In an older home around Cosham, damp from a failed joint can get into timber and plaster, which is far harder to put right than the sealant itself.
Commercial jobs are quoted on the same basis as homes: the amount of work, the access and the products needed, plus any working-time requirements on site. Call for a quick quote and we’ll go through it with you.
Why us?
- Anti-fungal silicone where joints get wet
- Full insurance on every job
- Rated 4.9 stars on Google
- More than 20 years in sealant work