Thinking about retrofit? Start with these DIY wins

Around 25% of a home's heat can escape through an uninsulated roof. Adding loft insulation slows this heat loss, helping your home stay warmer for longer while reducing heating bills and reducing your carbon footprint. 

Loft insulation is widely regarded as one of the most cost-effective energy efficiency improvements you can make. If you're considering improving your home's energy efficiency, loft insulation is often one of the simplest and most cost-effective places to start.

For many homes, yes. Adding mineral wool insulation between and across loft joists is well within the capabilities of many homeowners, provided the loft is dry, well ventilated and easy to access. 

You should consider using a professional if: 

• You are insulating the roof rather than the loft floor 
• Your loft has signs of damp or timber decay 
• Access is difficult or the roof has a very shallow pitch 
• Electrical cables or equipment require alteration 
• Spray foam or blown fibre insulation is being installed 
• Your home has complex roof shapes or raised ceilings.  

Keep this as a simple checklist: 

✔ Loft is dry 

✔ No signs of timber decay 

✔ Good ventilation 

✔ Safe access 

✔ You know where electrical cables are 

Key things to remember 

• Don't block eaves ventilation. 
• Aim for at least 270mm (or more where practical). 
• Don't squash insulation under storage boards. 
• Insulate and draught proof the loft hatch.
• Don’t cover high power electrical cables
• Use downlight covers
• Consider sealing obvious air leaks before adding insulation. 
• Every loft is slightly different, so it's worth taking a few minutes to assess its condition before buying materials. 

Many people worry they'll lose storage space after adding insulation. 

Fortunately, you can have both. 

If you're insulating the loft floor, raise the boarding above the insulation using: 

• Timber battens  
• Raised boarding systems designed for DIY 

 This prevents the insulation being compressed, which would reduce its effectiveness and could increase the risk of condensation.  

DIY Difficulty Rating 

★★★☆☆ 

Typical project time: Half to one day 

Best insulation type for DIY: Blanket (mineral wool or sheep's wool) 

Suitable for beginners? Yes, with safe loft access 

Professional help needed? For spray foam, blown fibre, warm lofts, damp or complex roofs 

Biggest benefit: Lower heating bills, warmer home and improved comfort 

Even homes with good insulation can feel cold if warm air is escaping through small gaps around doors, windows and floors. These unwanted air leaks (draughts) make your home feel colder, meaning you often turn the heating up to compensate. 

Draught proofing is one of the cheapest and easiest retrofit measures you can carry out yourself. It helps to: 

• Keep warm air inside your home. 
• Stop cold air getting in. 
• Improve comfort by reducing cold spots. 
• Lower heating bills. 
• Complement other retrofit measures such as loft or floor insulation.  

It's an excellent first step if you're new to DIY energy improvements, giving you a quick way to improve comfort while building confidence for future projects.  

For almost all homes, absolutely. Many draught proofing products are designed specifically for homeowners to install themselves and require little more than a tape measure, scissors and a screwdriver. 

Most people can successfully: 

• Fit draught proofing strips. 
• Seal small gaps with decorator's caulk or silicone. 
• Install brush strips on doors. 
• Fit chimney balloons. 
• Add draught excluders. 
• Seal skirting board gaps.  

Professional help is only usually needed for more specialist work, such as chimney caps, repairing damaged windows or carrying out airtightness improvements as part of a whole-house retrofit. 

Seal draughts, not ventilation. A draught is an unintended gap that lets cold air into your home. Ventilation is deliberate. It removes moisture and stale air, helping prevent condensation and mould. 

Never block or seal: 

• Air vents 
• Extractor fans 
• Boiler flues 
• Combustion air vents 
• Air bricks 

 If you're unsure whether an opening provides ventilation, leave it alone or seek advice before sealing it. 

Remember, the aim is to stop unwanted draughts while keeping your home properly ventilated and healthy.

DIY Difficulty Rating 

★☆☆☆☆ 

Typical project time: 1–4 hours 

Best for beginners? Yes 

Typical cost: £10–£100 

Professional help needed? Rarely, except for specialist chimney or window work 

Biggest benefit: Improved comfort, fewer cold draughts and lower heating bills 

Around 10% of a home's heat can be lost through the floor. If your ground floor feels cold underfoot, or you notice draughts around floorboards, underfloor insulation can make a noticeable difference. 

Insulating beneath the floor helps to: 

• Keep heat inside your home. 
• Reduce cold floors and draughts. 
• Improve comfort throughout the house. 
• Lower heating bills. 
• Complement loft insulation and draught proofing as part of a whole-house retrofit.  

Underfloor insulation is one of the more challenging DIY retrofit projects, but in the right home it can make rooms feel noticeably warmer and more comfortable.

Sometimes, it depends on your floor type. If you have a suspended timber floor with good access underneath (for example via a cellar or crawl space), installing insulation between the floor joists is achievable for experienced DIYers. 

However, it is considerably more demanding than loft insulation. You'll often be working in awkward positions, lifting floorboards or crawling beneath the floor while ensuring ventilation isn't blocked. 

If your home has solid floors, this work is usually only worthwhile as part of a larger renovation project. 

Check: 

✔ What type of floor do you have? 

✔ Is there any damp or timber decay? 

✔ Are air bricks clear? 

✔ Can you safely access beneath the floor? 

Key things to remember 

• Never block underfloor ventilation. 
• Support insulation properly. 
• Don't compress insulation. 
• Repair any damp or structural issues first. 

If you're unsure what type of floor you have, it's worth finding out before planning any insulation work, as this will determine whether the project is suitable for DIY. 

DIY Difficulty Rating 

★★★★☆ 

Typical project time: 1–3 days depending on access 

Best for beginners? No, better suited to experienced DIYers 

Suitable floor type: Suspended timber floors 

Professional help needed? Usually for solid floors or difficult access 

Biggest benefit: Warmer floors, fewer draughts and improved comfort