• Home
  • DIY
    • 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
Facebook Twitter Instagram
lets-do-diy.com
  • Home
  • DIY
    • 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
lets-do-diy.com
You are at:Home»Projects and advice»Insulating the rafters

Insulating the rafters

Summary: Learn how to insulate the rafters.


There two main reasons for insulating the roof: to save heat energy and when converting the attic into an additional room.

When insulating between the rafters in the attic, firstly ensure there isn’t a leak in the roof. Check it out to avoid complications at a later date. This is especially important, as leaks are hard to spot after insulation has been installed.

There are two types of insulating material designed for this job: blanket insulation and semi-rigid fibre insulation batts.

Another factor to consider is condensation caused by the underside of the tiles becoming very cold. This problem can be overcome by providing adequate ventilation.


Fix lengths of treated timber to the inside edges of each rafter to create a ventilation space.
Fit the insulation material between the battens.
Create a vapour barrier by stapling polythene sheeting to the rafters over the blanket.
If required, a solid finish can be achieved by covering the rafters with sheets of plasterboard.

Insulating loft rafters

  • To ensure there is adequate ventilation you need to create a 50mm (2in) space between the insulation and the tiles. This can achieved by fixing lengths of treated timber 50mm (2in) thick to the inside edges of each rafter. The timber should be screwed to the rafters as hammering in nails could dislodge the roof tiles.
  • Measure the width of the gap between the rafters and cut the insulation material to the correct size. Fit it between the rafters maintaining the 50mm (2in) gap you’ve created between the roofing felt and the insulation.
  • A vapour barrier should be included on the warm side of the insulation. Some blanket insulation material has a foil backing which when fitted with the foil facing into the loft acts as a vapour barrier. If using un-backed insulation blankets a vapour barrier can be created by stapling polythene sheeting to the rafters over the blanket.
  • Having completed fitting the insulation material and vapour barrier, depending on what the roof space is to be used for, a finish material can be fixed to the rafters. This could take the simple form of building paper stapled to the rafters allowing different sheets to overlap by at least 100mm (4in) and taping the joins with an adhesive waterproof tape.
  • Alternatively, a more solid finish can be achieved by covering the rafters with sheets of plasterboard. Use screws to fix the boards to the rafters, staggering the joints between the boards. Although a little more expensive, plasterboard screws tend to hold the board more firmly in place.






















Tools needed

  • Screwdriver
  • Tape measure
  • Staple gun

Materials needed

  • Treated timber
  • Screws
  • Foil-backed insulation
  • Polythene sheeting if the insulation has no foil on the back
  • Building paper OR plasterboard

Related projects

  • Insulating a loft
  • Lagging pipes, radiators and cylinders

Related cost guides

  • Average air heat pump cost
  • Average boiler cost
  • Average cavity wall insulation cost
  • Average underfloor heating cost
  • Average central heating cost
  • Average chimney repair costs
  • Average cost of a hot tub
Recent Comments
  • Anonymous on Average air source heat pump cost (2022)
  • Reggie on Prepare your home for moth season
Latest News
0

Design trends for 2022 and 2023

0

Product Review: Handsaws

0

Product Review: Claw hammers

1

Prepare your home for moth season

Popular Guides

Average cost of a septic tank

Average solar panels cost

Average fence installation cost

Average cost to install a toilet

Popular Projects

Laying wood flooring

Putting up a ceiling rose

How to troubleshoot electrical problems

Hanging a gate

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

© 2022 lets do diy ltd
  • 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