Buckinghamshire · England
Penn Street New Build Mastic
We cover Penn Street for plot mastic for developers and snagging failed sealant in new homes. Old material cut out, joints cleaned and sealed neatly.
- Gaps behind new kitchen upstands
- Cracks appearing as a new home settles
- Sealant that never bonded to the surface
New build mastic in Penn Street
New homes move as they dry out. Timber dries and shrinks, and baths and trays settle, so sealant that was laid quickly before handover often cracks. We work on kitchens, windows & doors and bathrooms & en suites, and the jobs we see most are frame joints opening as the plaster dries and kitchen sealant that has pulled off the wall.
Around Penn Street, older homes often have timber floors that move through the year, which is why skirting and threshold joints need a flexible sealant, not filler.
All of our work is guaranteed for twelve months, in Penn Street and everywhere else we cover.
- Place
- Penn Street (HP7)
- Region
- Buckinghamshire
- Cover
- One year on every job
- Quotes
- A clear quote up front
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
What happens on the day
On the day, we start by going over the job with you. We protect the surfaces around the joints before we start. The work normally takes a few hours for most snagging lists, longer for a run of plots. In a small place like Penn Street, access is usually the main thing to plan. If the job is outside, mention outbuildings, exposed walls and how to reach them.
- We start by going through the snagging items or plot schedule with you.
- The failed sealant is removed completely down to clean surfaces.
- Joints are vacuumed and cleaned of building dust.
- We prime where needed and apply a sealant suited to each joint.
- Each bead is tooled and the cure times explained.
Getting ready for the visit
- On commercial sites, let us know about site rules
- Tell us if parking is tricky
- Tell us about any water getting in
How to get a quote
If you are in Penn Street and need new build mastic, ring 0345 464 0079 or send us an email. Tell us what the problem is and where, and you’ll get a clear quote before we start.
Related advice
Work for landlords, hotels and businesses
Hotels need rooms back in use, so the work can be planned room by room. We’ve worked in hotels as well as homes and businesses.
Landlords and agents in Penn Street can book us as well as homeowners. Sealant work between tenants keeps a property looking cared for before the next move-in.
Should I try it myself first?
A careful DIYer can reseal a simple joint, like a short, easy-to-reach joint indoors. The common mistakes are sealing over old sealant, sealing a damp joint and using far too much.
The biggest DIY mistake is sealing over old sealant. Silicone does not stick to old silicone, so it peels away and traps moisture behind it. All the old material has to come out first.
When something else is needed
To be straight with you, there are a few things sealant will not fix:
- Settlement cracks that need a surveyor
- Damaged fittings that need replacing
- Movement caused by a poorly fitted tray or bath
Not sure which it is? You can ring 0345 464 0079 or send us an email and we’ll tell you honestly.
Where we work in Penn Street
- Bathrooms & en suites
- Skirting & floors
- Show homes
- Windows & doors
- Plot handovers
- Kitchens
Towns and villages near Penn Street
Other services in Penn Street
What new build mastic looks like in Penn Street
Rainfall in the South East is lower than in much of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast.
For new homes near Amersham station, it’s worth checking the sealant early, while snags are still fresh.
Penn Street is about 3 miles south-west of Amersham, in Buckinghamshire. Jobs in Penn Street get the same care as everywhere else we work: the old material taken out, joints prepared properly and a 12-month guarantee. Across Buckinghamshire, we cover 263 places, Penn Street among them. For nearby work, see our Reading page, about 20 miles away.
All of HP7 is within our area for new build mastic, from the main roads to the quietest streets. We also cover Woodrow (1 mile east), Mop End (1 mile north), Beamond End (1 mile north-west), Winchmore Hill (1 mile south-east) and Coleshill (2 miles south-east). Further out, we also cover Aylesbury (13 miles north-west), High Wycombe (4 miles south-west), Chesham (4 miles north-east), Marlow (8 miles south-west), Amersham (3 miles north-east) and Beaconsfield (3 miles south).
Near you in Penn Street
We work in homes and buildings around The Squirrel pub and Holmer Green Senior School. For rail, the closest station is Amersham station, about 2.6 miles north-east of the centre. A little further out are Great Missenden (2.7 miles north) and Amersham Hospital (1.8 miles east). Open spaces near Penn Street include Gomm's Wood.
Questions from Penn Street
Can you do new build mastic in Penn Street?
Yes. Our work covers London and the South East, and Penn Street is part of that. Just ring 0345 464 0079 or email us with a few details of the job, and we will give you a clear quote.
I let a flat near Amersham station. Can you help?
Yes, we work for landlords and letting agents. You can phone 0345 464 0079 or email us with the address and a few details, and we will give you a fixed price before we start.
Can you reseal over the builder’s sealant?
No. Sealing over old sealant looks fine for a few weeks, then lifts. All the old sealant comes out before we start.
How much does new build mastic cost in Penn Street?
The cost depends on the size of the job, access and how much old sealant has to come out. Ask us for a quote.
Why has my new-build shower seal failed already?
Cracking in the first couple of years is common as timber and plaster dry out. Poor preparation at handover adds to it.
When is the best time to reseal in a new build?
Any seal that’s leaking should be redone straight away. For small cosmetic gaps, waiting until the house has settled can save doing them twice.
Do you work for developers?
Yes. We work through plots to your schedule. Get in touch with the number of plots and the scope and we will quote.
My new home is still under warranty. Should I contact you?
Start with the builder if you’re in the snagging or warranty period. Once that’s done, or if they will not put it right, we will cut it out and reseal it.
Why act early in Penn Street
Water getting past a failed seal in a new build reaches walls and floors that are still settling. Dealing with it early keeps the damage away from ceilings, floors and finishes. Where a wall is exposed, as many are in small places like Penn Street, wind-driven rain gets into any failed joint, and older walls, once damp, take a long time to dry.
Every job is a little different, so each one gets its own quote. Size, access and the product the joint needs all play a part.
Why choose Mr Mastic in Penn Street
- ARBOMaster approved applicator
- Anti-fungal silicone where joints get wet
- More than 20 years in sealant work
- We leave the area clean and tidy
Read what affects the cost and what customers say.
Common problems we fix in Penn Street
Baths and trays settle under load once the home is lived in. A bath sealed empty drops slightly when filled, straining the joint.
The problems people usually mention when they call include:
- Untidy sealant flagged on a snagging list
- Internal frame sealant that has split
- Beads laid onto grit and dust from the build
- Worktop and upstand sealant coming away
Around Penn Street, as everywhere, new build mastic is only as good as the preparation behind it.
Before you book anyone
- What guarantee comes with the work
- When the joint can take water or movement
- Which colour the sealant will be
- Who does the work, and how experienced they are
What affects the cost of new build mastic
There’s no set price list, because jobs vary so much. The quote depends on:
- When we can work, for business premises
- Which sealant suits the joint
- How easy the joints are to reach
- Whether old sealant or filler has to be cut out
Commercial jobs are quoted on the same basis as homes: the amount of work, the access and the products needed. Ask us for a quote and we’ll go through it with you.
What we need to know
When you call or email, it’s useful to know:
- How many joints, rooms or windows are involved
- Whether it has been sealed before
- Access, such as stairs, a lift or height
- What’s wrong with the joints now
For a quick quote, get us on the phone, or email us if that is easier. Describe what needs sealing and we’ll talk you through the work.