Stefan
Mo is a star. Cheerful. Good at his job. Very tidy (clean, waste in his own rubble bag, takes everything away) and keeps his appointments 100%.
House extensions in Noord-Holland
More space without moving house. Klusbedrijf MSZ builds extensions throughout our service area in Noord-Holland, from Hilversum and Bussum to Huizen and Weesp. We do everything, from the foundation to the flat roof and the sliding doors, and you get a quote with a fixed price beforehand.
In het Gooi most people live in a single-family home, often with a garden.
Feel free to send us a photo on WhatsApp first — that way we can often assess the problem straight away.
5.0 on Werkspot
225+ reviews
Available 24/7
Nights and weekends too
Registered with the KvK
KvK 87844508
Family business
From Almere, since 2022
Prices up front
No surprises
- IN HET GOOI AND WEESP
Extensions in het Gooi and Weesp: ground, space and rules
In Hilversum 88% of homes were built before 2000, in Gooise Meren (Bussum, Naarden, Muiden, Muiderberg) 91% and in Huizen 89%. Single-family homes dominate: 58% in Hilversum, 71% in Huizen and 86% in Blaricum (CBS, 2023). With 58 to 86% single-family homes, most houses in het Gooi have a garden, and so room for an extension, covered patio or garden building. Hilversum, Laren and Blaricum are on the sandy soil of het Gooi; around Weesp and Muiden the ground is softer. A large share of homes in het Gooi are older, with many pre-war houses in Hilversum and Bussum. Homes built before 1960 can still have lead or old iron pipes; lead was banned in 1960.
On the sandy soil of het Gooi an extension is easy to found; around Weesp and Muiden we look extra carefully at the ground.
See also all about house extensions.
- NEAR YOU
An extension throughout our service area in Noord-Holland
We build extensions in every town in our Noord-Holland service area, from Hilversum and Bussum to Huizen and Weesp. From Almere we drive there via the Hollandse Brug. For an extension we like to come and have a look first, so that the quote matches your home.
A visit in Noord-Holland comes with one fixed call-out charge: €42.35 incl. VAT (€35 excl. VAT). You know the amount before we set off; it never appears afterwards as an extra on the invoice. If we do several small jobs in one visit, we only charge the call-out charge once.
Map of Noord-Holland
This map comes from Google Maps. Only when you click the button is the map loaded and does Google receive data, such as your IP address.
Or open Google Maps in a new tab- REVIEWS
What customers say about us
All our reviews are on Werkspot, an independent platform. They come from real customers and we cannot change them ourselves. From het Gooi and Weesp we received 22 reviews on Werkspot, all with 5 stars. Stefan from Bussum wrote about his toilet in April 2025: “Very tidy (clean, waste in his own rubble bag, takes everything away) and keeps his appointments 100%.”
Reviews translated from Dutch.
- CUSTOMERS IN HET GOOI AND WEESP
What customers in het Gooi and Weesp say
Of the 22 Werkspot reviews from het Gooi and Weesp, 6 were about a leak or the water pipe, 4 about the toilet, 4 about the shower and 4 about a drain that was blocked or had to be moved. Werkspot is an independent Dutch platform. A few reviews about jobs like this:
Daan from Blaricum, August 2024: “Top service and speed, solved a problem that few people could.”
Erwin from Huizen, January 2026: “Friendly guy, clear in communication, listens to your own idea and adds his knowledge and advice.”
- FREQUENTLY ASKED QUESTIONS
Questions about an extension in Noord-Holland
Is your question not listed? Feel free to call or WhatsApp us, also outside office hours.
Do I need a permit for an extension in het Gooi and Weesp?
Often not at the back, but that depends on the size and position. Each municipality in het Gooi has its own environment plan; in Naarden-Vesting and the village centres there are often extra rules for appearance. Do the permit check on the Omgevingsloket first.
What should I watch out for with the foundation in het Gooi and Weesp?
Hilversum, Laren and Blaricum are on the sandy soil of het Gooi; around Weesp and Muiden the ground is softer. We match the foundation to the ground and to the existing home.
Which jobs do you do most often in het Gooi and Weesp?
Of the 22 Werkspot reviews from het Gooi and Weesp, 6 were about a leak or the water pipe, 4 about the toilet, 4 about the shower and 4 about a drain that was blocked or had to be moved.
An extension in Noord-Holland?
Send us a photo of the back of your house and tell us the measurements you have in mind, on WhatsApp or through the quote form. We will make an appointment and give you a quote with a fixed price.
