Types of Loft Conversion
There are several types of loft conversion, each suited to different property styles and budgets:
- Velux (roof light) — the simplest and cheapest option, adding windows to the existing roof structure. Typically costs £20,000 to £35,000.
- Dormer — extends the roof with a box-shaped structure, creating more headroom and floor space. Costs around £30,000 to £60,000.
- Hip-to-gable — converts a hipped roof into a gable end, popular on semi-detached homes. Costs £40,000 to £65,000.
- Mansard — alters the roof structure significantly to create maximum space. Costs £45,000 to £75,000 or more.
Your choice will depend on your property type, the existing roof structure, your budget and local planning rules.
Planning Permission and Regulations
Many loft conversions fall under permitted development rights, meaning you won't need planning permission as long as you stay within certain limits. These include a maximum volume addition of 40 cubic metres for terraced houses or 50 cubic metres for detached and semi-detached properties.
However, if your property is in a conservation area, is a listed building, or if the conversion involves raising the roof height, you'll need to apply for planning permission. All loft conversions require building regulations approval and a structural engineer's sign-off.
How Much Value Does a Loft Conversion Add?
A well-executed loft conversion can add up to 20% to your home's value, making it one of the highest-return home improvements you can make. Adding a bedroom with an en-suite bathroom is particularly valuable, especially in areas where family-sized homes command a premium.
The key is ensuring the conversion feels like a genuine room rather than a converted attic. Good natural light, sufficient headroom, proper insulation and quality fixtures all contribute to maximising the value uplift.
Using a Remortgage to Fund It
Remortgaging lets you borrow the cost of the loft conversion at mortgage interest rates, which are typically much lower than personal loan or credit card rates. For a £40,000 loft conversion, the difference in interest between a mortgage rate and a personal loan rate could save you thousands over the repayment period.
You'll need enough equity in your home to cover both your existing mortgage and the additional borrowing. Since the loft conversion will increase your property's value, the effective cost to your equity position is often less than the amount you borrow — a strong financial argument for this type of improvement.
Important: Your home may be repossessed if you do not keep up repayments on your mortgage. There will be a fee for mortgage advice. The actual rate available will depend on your circumstances. Think carefully before securing other debts against your home.