Utrecht · approx. 25 km from Utrecht
Sealant work in Amersfoort
Amersfoort lies on the edge of the Utrechtse Heuvelrug, where the sand gives way to the clay and peat of Eemland. On sand a house stays still; on the wet side the ground around it moves and a house on shallow foundations keeps settling. That movement determines, together with the thermal movement of the building components themselves, how wide the joint needs to be. Sealant does not solve the settlement itself. That movement determines the width.
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What matters in Amersfoort
Two kinds of ground under one city
A medieval core with houses built on the old town wall, a railway district and pre-war villas, post-war reconstruction districts from the 1950s and 1960s, and the new-build districts of Kattenbroek, Nieuwland and Vathorst.
The Soesterkwartier grew from around 1900 along with the marshalling yard and the Wagenwerkplaats: timber window frames, putty and glazing sealant. The Bergkwartier and the Leusderkwartier are pre-war: villas on the Berg, 1930s terraces and semi-detached houses in the Leusderkwartier, both on the sand and with a lot of timberwork. Liendert is from the 1960s. Kruiskamp is mixed: low-rise from the 1920s and 1930s with medium-rise from the 1950s in between. Randenbroek has been partly renewed. Kattenbroek was built in the early 1990s, Nieuwland between 1995 and 2001, Vathorst from 2001 onwards. There, plastic and powder-coated aluminium window frames sit in brickwork and prefabricated concrete components, and those connection joints are now due for their first replacement.
Kattenbroek, Nieuwland and Vathorst were put up in a short time and phase by phase. What was sealed in the same years is also worn out in the same years: street after street. On top of that comes the ground: on the north side the clay and peat of Eemland, which thin out against the ridge, and on the south side the sand of the Amersfoortse Berg. On the wet side a connection joint has more movement to deal with. That is why the joint width here follows from that movement, with 8 mm as the minimum. Joints wider than 30 mm fall outside our terms and conditions.
The city centre is low-traffic and cameras read your number plate. You register a visitor's number plate up to 48 hours in advance, and for a visit to a business that can still be done up to a quarter of an hour after driving in. Loading and unloading is allowed in the core shopping area between seven and eleven in the morning, and on Monday, Tuesday, Wednesday, Friday and Sunday also between half past five and half past seven in the evening. That same core shopping area has been a zero-emission zone for commercial vehicles since 1 January 2025; from 1 January 2027 that also applies to the rest of the low-traffic city centre. There is a transitional arrangement for existing vans, so whether a van is allowed in depends on the number plate and the date of first registration. In De Laak a lot of parking is in courtyards inside the housing block, behind the homes, so there the hose often has to go the long way round.
From our base in Utrecht it is 25 kilometres along the A28. Outside the rush hour that takes about half an hour; in the rush hour it can rise considerably. That is why we would rather be at your door here at half past eight than at eleven. So a bathroom or a few window frames is perfectly doable here.
What we do in Amersfoort
- Bathroom, sanitary & kitchenSealing of sanitary ware, showers, baths, washbasins and kitchens.
- Window frames & glazingNeat, durable sealant work around window frames and glass.
- Facades & structural jointsFacade joints, connection joints and expansion joints in floors and walls.
- Swimming pool & wellnessSealant work in swimming pools, saunas, steam rooms and spas.
- Renovation & maintenanceSealant work during renovation, repairs and periodic maintenance.
- Specialist sealant workFor specific requirements and specialist applications.
You will hear from us within 15 minutes on working days, and the work comes with a 2-year guarantee.
The work here
What we do most often in Amersfoort
Connection joints on plastic and aluminium
In Kattenbroek, Nieuwland and Vathorst you come across many plastic and powder-coated aluminium window frames, connecting to brickwork and prefabricated concrete components. Those materials do not move in step: PVC expands by 70 to 80 millionths per degree, aluminium by 23 to 24, concrete by 10 to 12. The connection joint has to accommodate that difference. That is why the movement determines the width, with 8 mm as the minimum.
More about this serviceBathrooms from around 2001
The first residents of Vathorst have lived there for well over twenty years. By then sanitary sealant has usually had its day: hard, discoloured or loose along the tile edge. If acrylic was used, the shower water has dispersed it. Silicone or a hybrid with fungicide belongs there, at least 8 mm wide and 6 mm deep.
More about this serviceNatural stone in the old town
The city centre is full of bluestone sills and natural stone in brick facades. Acetoxy silicone does not belong there: on an alkaline substrate it loses its adhesion. Free plasticisers migrate into the pores as a dark edge, often only visible after weeks, and that edge-zone staining is irreparable. Polishing does not help.
More about this serviceHow we approach it here
Which sealant on what, and what it costs
The substrate decides the sealant
In the city centre and along the Muurhuizen it is bluestone, brickwork and old painted timber. There, natural stone sealant with chemically bound plasticisers goes in and never acetoxy silicone, because that loses its adhesion on alkaline masonry. In the Soesterkwartier and the Bergkwartier painted timber predominates: if paint has to go over the joint, it becomes acrylic or an overpaintable hybrid, because paint does not adhere to silicone. In Kattenbroek, Nieuwland and Vathorst you mainly come across plastic and powder-coated aluminium window frames, connecting to brickwork and prefabricated concrete components, and glazed tiling in the bathroom. Smooth and dense, so there the preparation decides whether the sealant stays put.
Costs and lead time
We charge per linear metre, and there is a sliding scale based on the size of the job. In Kattenbroek, Nieuwland and Vathorst a whole row was built at the same time and sealed at the same time, so the sealant at your neighbours' is as old as yours. The sliding scale is about the number of metres in a single order. How much work fits into that, we agree in advance. For a homeowners' association (VvE) it works the same way: all the bathrooms of a complex at once are more metres in a single order than one bathroom on its own. The rates have not been fixed yet, so you will not get an amount here that later turns out to be wrong. One thing is certain: here it is almost always about replacement, and that costs more than new work. The old sealant has to come out completely first, because sealant does not adhere to sealant, and that cutting out is most of the work. If there is a sanitary joint among it, put that at the start of the week: sealant cures at roughly 2 to 3 mm per 24 hours, and with one bathroom in the house you do not shower for two days. Our sealant work comes with a 2-year guarantee, whether that is one joint in the bathroom or the window frames of a whole housing block. If the building itself settles, that movement falls outside any guarantee. What we do is measure the joint in advance against the movement it has to take.
Two routes
Business or homeowner in Amersfoort
Isselt lies on the Eem, De Hoef and Kantorenpark Podium are office areas, and De Wieken-Vinkenhoef keeps growing at the Hoevelaken interchange. On such sites, contractors, painters and maintenance companies outsource the sealant work, and interior fit-out companies want a worktop or cabinet joint finished. That is the work we tender for. In the post-war reconstruction districts, sealant work goes along with the planned maintenance of housing association stock; in Nieuwland and Vathorst it sits with homeowners' associations (VvE). Send the specification or the work description, and you get a price per metre with a sliding scale on the total.
For businesses
Contractors, painters, homeowners' associations, property managers and interior fit-out.
See what we do for businessesAlso near Amersfoort
As the crow flies from the centre. By road it is further.
- Leusden 6 km
- Hoevelaken 5 km
- Soest 6 km
- Bunschoten-Spakenburg 8 km
- Woudenberg 10 km
- Nijkerk 9 km
- Baarn 9 km
Is your town or city not listed? See the whole service area.
Questions from Amersfoort
What people in Amersfoort ask most often
My house in Vathorst dates from 2004. Is the sealant work already due?
After well over twenty years that is quite possible. A sanitary joint does not last forever, and outside on the south side it goes faster. More reliable than a number is looking: does the joint feel hard, is it coming away along the flank, or is there a crack down the middle? The last means that the joint is too narrow and refilling solves nothing. Look in winter: the building components are then contracted and the joint is at its widest.
Our bathroom in Vathorst was only recently resealed and yet the black edges are back already. Is that down to the sealant or to something else?
Usually not the sealant but the air. A bathroom in a new build must be able to extract 14 dm³ per second; if the ventilation is on low or the vent is closed, the moisture hangs around and mould grows on every joint. Do not scrub that joint with chlorine: chlorine-based cleaners wash the anti-mould agent out of the sealant and make the edge porous. Then it comes back faster than before.
We live in De Laak on the waterside. Why does the sealant on that side wear out sooner?
A facade on the water stays wet longer and dries more slowly. For that exposure, a closed-cell PE backing rod belongs behind the joint, not open-cell PU, because open cell soaks up moisture. And the joint may adhere on two sides only, not to the base. If it adheres on three sides, the middle cannot stretch and it cracks open.
Our property in the city centre is a listed building with bluestone sills. Can ordinary silicone go on that?
No. Bluestone contains lime, and on such an alkaline substrate an acetoxy silicone comes away sooner or later. The real problem, though, is the stain: free plasticisers and silicone oil migrate into the pores and draw a dark edge along the joint, sometimes only visible after weeks. A sill sits right on the pavement, so everyone walking past sees it. You cannot get that edge out again, polishing does not help. On bluestone, natural stone sealant with chemically bound plasticisers goes in, and for a listed building we put forward beforehand what goes in.
In the Bergkwartier the sealant around our windowpanes is crumbling. What now?
With glazing sealant and putty from before 1994, no knife of ours goes in until it is established what is in it. That material is suspected of containing asbestos, risk class 2 as standard: first an asbestos survey, then a demolition notification, and removal by a licensed company. Once that has been done, or it turns out to be clean, we take on the glazing and the connection joints. The same applies everywhere the glazing dates from before 1994, so also in the Soesterkwartier, the Leusderkwartier and the post-war reconstruction districts.
