Dormer or hip to gable loft conversion
10-12 weeks
Dormer conversions are the most popular with homeowners. This is a structural extension which projects vertically from the slope of the existing roof, creating a box shape. Because this loft extension generally requires no dramatic changes and allows for the installation of conventional windows, it only requires a couple more weeks to complete with compared to a room in loft project.
If a dormer isn’t for you, you might also consider a hip to gable alternative. Ideal for end of terrace and detached homes, a hip to gable loft conversion straightens an inwardly slanted end roof to create a vertical wall. This small change can make a huge difference to the feel of the living space inside, and is becoming an increasingly popular option for homeowners. Much like the dormer, the small amount of work required to the roof keeps construction timings modest.
Mansard loft conversion
10-16 weeks
A mansard loft conversion is constructed by raising the party wall (the wall shared with your neighbours). The roof remains flat, while one outer wall slopes gently inwards. Mansards are typically found at the rear of the house, and although they are suitable for many property types, they are most popular in terraced houses.
Because this kind of loft conversion requires heavy reconstruction of the roof, along with the erection of that party wall, this is the most time-intensive. What’s more, as it requires work to the party wall, your neighbours might set restrictions on construction hours, to minimise disturbance to their household.
Garage
4-6 weeks
Much like a room in loft conversion, because your builder will be working with an existing structure, timings can be kept to a minimum. However, unlike a loft, with a garage, you’ll also have to factor in the time needed to replace your garage doors with a new wall.
Side return or rear extension
10-16 weeks
Whether you’re extending your home out towards the back of the property or utelizing some dead alleyway space to the side, you’ll be looking at similar timelines for both.
Typically, construction will be broken down into these stages:
- Preparation
- Foundations and groundwork
- Ground and low-level work
- External and internal walls
- Building of the roof
- Laying down the roof covering
- Guttering, windows, doors and render
- Knock through and plastering
- Finishing touches, such as electrics and plumbing
- Final tidy up
It’s worth bearing in mind, your timings will be affected by the side of your extension and complexity. For instance, if you include a floating corner or glass ceiling, these structural features will require extra time.
Two-storey extension
16-24 weeks
Two-storey extensions take a classic rear extension and use it to add another space to the upstairs of the house. Because of this extra storey, you can expect all the work involved with a rear extension, plus the work required for that second storey.
Depending on both the size and complexity of your project (see above), you could be waiting up to 6 months for construction on your home to be complete.
Converting a basement
10-14 weeks
Unlike converting a garage, a basement conversion is likely to be a big job. In 99% of cases, you’ll need to allow time for both excavations and underpinning, alongside more cosmetic elements.
What’s more, it’s likely your basement will be difficult to access, making work that little bit more tricky. While skilled contractors can navigate hard to reach basements, there will be a time delay on the work.
Retrofitting a basement
20 - 24 weeks
And lastly, should you lack a basement to convert, you’ll need to retrofit one. These are becoming more common in London, where space is at a premium. They involve excavating a new level under an existing property before a new set of rooms is added to the home.
If your home is suitable for such an extension, over the 20-24 weeks, construction will involve...
- Preparation
- Exposing the foundations
- Underpinning
- Excavation and waste disposal
- Installing structural support
- Reinforcement of basement floor
- Adding damp proof membrane
- Creating a drain waterproofing system
- Erection of new walls
- Adding windows and stairwell
- Creating new suspended ceiling
- Finishing touches, such as electrics and plumbing
- Final tidy up
Needless to say, it’s no small project, but in areas like London, this could add insane amounts of value to your home.
Learn more about adding value.
What affects construction timings?
Of course, the timings we’ve listed here are just the UK averages. How long your own project will take will depend on a number of factors, such as…
- Size of the project
- Complexity
- Location
- Access to the construction site
- Size of the construction team
- Weather
- Use of long-lead items, such as bi-fold doors and kitchens
Not to mention, whether or not your project is hit with any unforeseen delays. This could be certain materials taking too long to arrive or problems with equipment.
Want to learn more about construction? In need of some advice about a home extension? At Resi, we run a free consultation service. Simply book in a time with our team and we’ll answer all your burning project questions!
