• Home
  • DIY
    • Self build
    • Projects and advice
      • Bathroom
      • Building, brickwork and masonry
      • Ceilings
      • Cleaning
      • Concrete work
      • Damp, rot and infestation
      • Drains
      • Electrical
      • Fireplaces
      • Floors
      • Garden
      • Heating
      • Insulation
      • Kitchen
      • Lighting
      • Lofts
      • Painting and decorating
      • Plasterwork
      • Plumbing
      • Roof and guttering
      • Safety
      • Security
      • Tiling
      • Walls
      • Windows
      • Woodwork
    • Glossary
    • Know your tools
    • Know your materials
  • Cost guides
  • News
  • Community
Facebook Twitter Instagram
lets-do-diy.com
  • Home
  • DIY
    • Self build
    • Projects and advice
      • Bathroom
      • Building, brickwork and masonry
      • Ceilings
      • Cleaning
      • Concrete work
      • Damp, rot and infestation
      • Drains
      • Electrical
      • Fireplaces
      • Floors
      • Garden
      • Heating
      • Insulation
      • Kitchen
      • Lighting
      • Lofts
      • Painting and decorating
      • Plasterwork
      • Plumbing
      • Roof and guttering
      • Safety
      • Security
      • Tiling
      • Walls
      • Windows
      • Woodwork
    • Glossary
    • Know your tools
    • Know your materials
  • Cost guides
  • News
  • Community
lets-do-diy.com
You are at:Home»Projects and advice»Fitting a roof window

Fitting a roof window

Summary: Learn how to fit a roof (Velux) window, prepare an opening and fit a window.


A roof window – or skylight – can be an essential part of a loft conversion, transforming an ordinary attic space into a bright, attractive room. There are two types of roof window: curb mounted and framed-in-place. A curb mounted roof window stands vertical to the roof plane. A frame-in-place roof window fits flush with the plane of the roof.

Planning the Velux Window

When planning a roof window there are several important factors to consider.

  • Read the manufacturer’s instructions.
  • The window must be big enough to provide adequate lighting for the room. Generally speaking, the smaller the angle of the roof pitch the taller the window needs to be.
  • Position the roof window on the side of the house that receives the most light.
  • The window should be roughly located in the centre of the room.
  • The window should be positioned at a height so that you can see out of the window whether you are sitting or standing.
  • The top of the window should be within easy reach.
  • It is unlikely you will need planning permission to install a roof window, but to avoid any problems it is advisable to check especially if you are planning to work on a listed building or if the building is in a conservation area.

The framed-in-place roof window is the most common type and the easiest to fit. They are sold in complete kits consisting of the window and the surrounding flashing, which will be made from either galvanised steel or aluminium. The instructions below will give you a guide to installing a framed-in-place roof window into a slate roof.


Preparing the opening

  • Make sure the skylight is positioned so that one side of the window is aligned with a rafter. Check that none of the roof rafters are in the way, for these must not be cut without professional advice.
  • Mark the dimensions of the window given by the manufacturer on the inside of the roof felt.
  • Hammer a nail up through the roof at each corner of the window.
  • Using a roof ladder climb onto the roof and remove slates from inside the area marked out by the protruding nails. Take extreme care when working from height.
  • Then cut away the roof battens and roofing felt in the area marked out by the four nails.
  • Next cut through any rafters that are obstructing the window space. This can be either done from the roof or from inside the loft.
  • Using 2 x 4 timber – 100mm (4in) wide and 50mm (2in) thick – cut two horizontal trimmers and nail them between the rafters to set the height of the window.
  • Cut one vertical trimmer and nail in position to set the width of the window. Remember that one side of the window will be aligned to a rafter.

Fitting the window

The method of installation will vary according to the model of window you have bought. To install the window you will need suitable flashing. Many roof windows come with their own flashing kits. Fitting the window will require two people.

  • Before fitting the frame remove the glazed sash section.
  • Position the frame and fasten it in place using the brackets provided. Around the frame there will be a line marked, which indicates the level of the surrounding roof battens when the frame is in place.
  • Measure the diagonals of the frame to ensure it is square. If the measurements are equal then the frame is square.
  • Moving up on to the roof fit the flashing around the frame according to the manufacturer’s instructions. Secure the flashing as instructed with nails or roof cement. Start by fitting the sill flashing at the bottom of the frame. Then move up the sides of the frame. Finally, fit the flashing above the frame.
  • Replace the slates around the frame. It may be necessary to cut some of the slates so they overlap the flashing to meet the frame.
  • Replace the glazed sash section into the window.

Finishing

Some roof window kits come complete with a prefabricated lining that when fitted provides a neat, finished surround to the window. If this is not the case you will need to line the opening with plasterboard.

  • Cut the plasterboard to the required dimensions and nail in position to the timber around the frame.
  • Finish the joints with filler or jointing tape.
  • The entire loft can now be insulated. Plasterboard can be fitted to the rafters and then plastered.

Related projects

  • Joining pipes
  • Removing an air lock in a water pipe
  • Tap repairs
  • Burst pipe
  • Self cutting taps
  • How to cut pipe
  • How to replace a bath
  • How to replace a toilet
  • How to use a pipe bender
  • Push fit fittings

Related cost guides

  • Average dishwasher installation cost
  • Average cost of a hot tub
  • Average cost to install a shower
  • Average cost to install a bathroom sink
  • Average cost to tile a bathroom
  • Average cost to fit a bathroom
  • Average cost of a boiler

Recent Comments
  • Vic on Is Christmas a good time for DIY?
  • Anonymous on Average air source heat pump cost (2022)
  • Reggie on Prepare your home for moth season
Latest News
0

Potential DIY home improvement trends for 2023

1

Is Christmas a good time for DIY?

0

Design trends for 2022 and 2023

0

Product Review: Handsaws

Popular Guides

Average retaining wall cost

Average underfloor heating costs

Average TV aerial installation costs

Average cost to hire a cherry picker

Popular Projects

Wiring electrical circuits

Building steps

Window stays and fasteners

How to build a pond

DIY Categories
Bathroom
Building, brickwork and masonry
Ceilings
Cleaning
Concrete work
Damp, rot and infestation
Drains
Electrical
Fireplaces
Floors
Garden
Heating
Insulation
Kitchen
Lighting
Lofts
Painting and decorating
Plasterwork
Plumbing
Roof and guttering
Safety
Security
Tiling
Walls
Windows
Woodwork

Self Build Guide
How to find a building plot
Evaluating a building plot (2023)
How to get a self build mortgage
Self build construction options
Self build architect and design considerations (2023)
Self build planning permission and legal consents
© 2023 lets do diy ltd | ebuild
  • Home
  • About
  • Contact us

Type above and press Enter to search. Press Esc to cancel.

We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. By clicking “Accept All”, you consent to the use of ALL the cookies. However, you may visit "Cookie Settings" to provide a controlled consent.
Cookie SettingsAccept All
Manage consent

Privacy Overview

This website uses cookies to improve your experience while you navigate through the website. Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. We also use third-party cookies that help us analyze and understand how you use this website. These cookies will be stored in your browser only with your consent. You also have the option to opt-out of these cookies. But opting out of some of these cookies may affect your browsing experience.
Necessary
Always Enabled
Necessary cookies are absolutely essential for the website to function properly. These cookies ensure basic functionalities and security features of the website, anonymously.
CookieDurationDescription
cookielawinfo-checkbox-analytics11 monthsThis cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Analytics".
cookielawinfo-checkbox-functional11 monthsThe cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional".
cookielawinfo-checkbox-necessary11 monthsThis cookie is set by GDPR Cookie Consent plugin. The cookies is used to store the user consent for the cookies in the category "Necessary".
cookielawinfo-checkbox-others11 monthsThis cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Other.
cookielawinfo-checkbox-performance11 monthsThis cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Performance".
viewed_cookie_policy11 monthsThe cookie is set by the GDPR Cookie Consent plugin and is used to store whether or not user has consented to the use of cookies. It does not store any personal data.
Functional
Functional cookies help to perform certain functionalities like sharing the content of the website on social media platforms, collect feedbacks, and other third-party features.
Performance
Performance cookies are used to understand and analyze the key performance indexes of the website which helps in delivering a better user experience for the visitors.
Analytics
Analytical cookies are used to understand how visitors interact with the website. These cookies help provide information on metrics the number of visitors, bounce rate, traffic source, etc.
Advertisement
Advertisement cookies are used to provide visitors with relevant ads and marketing campaigns. These cookies track visitors across websites and collect information to provide customized ads.
Others
Other uncategorized cookies are those that are being analyzed and have not been classified into a category as yet.
SAVE & ACCEPT