Remortgage for Home Improvements, Extensions and Lofts

What is a remortgage for home improvements?

A remortgage for home improvements is a remortgage or further advance that raises additional borrowing secured on your home to fund work on that home. The money can pay for an extension, a loft or garage conversion, a new kitchen or bathroom, energy improvements, structural repairs or a wider renovation. Lenders commonly accept home improvement as a reason for capital raising, because the money stays in the property that secures the loan. Each lender decides which works it accepts and how much it will lend. The lender values the home as it is today, not as it will be once the work is done. The amount you can borrow for home improvements therefore depends on the equity you already have and on whether you can afford the new total loan.

A remortgage moves the whole mortgage to a new lender, a further advance adds borrowing with the lender you already have, and a product transfer changes the deal with your lender without borrowing more. Borrowing secured on a home you live in is normally a regulated mortgage, meeting the legal test that at least 40% of the property is used as a dwelling (legislation.gov.uk: Regulated Activities Order, article 61). The Financial Conduct Authority's conduct rules for mortgages, MCOB, require the lender to assess affordability before it lends or agrees to vary a mortgage (FCA Handbook: MCOB 11.6). A product transfer with no extra borrowing and no change likely to matter for affordability is exempt from that assessment. A further advance adds borrowing, so the assessment applies to it.

A remortgage or further advance normally pays out in one sum when it completes, and you pay the builder from it. Some homes cannot be lived in, or valued properly, until the work is finished: a home without a working kitchen or bathroom, for example, or one with serious structural problems. A standard lender may decline those cases or hold back part of the loan, and refurbishment finance or a short-term bridging loan may be needed first, with a mortgage once the home is habitable. A bridging loan secured on a home you live in is regulated too: the FCA treats a regulated mortgage contract with a term of 12 months or less as a bridging loan (FCA Handbook glossary: bridging loan). Buying a property to renovate it is a different case, covered on our page on renovation mortgages.

Mortgage Lane arranges finance for extensions, loft and garage conversions, kitchens and bathrooms, structural repairs, energy-efficiency upgrades and whole-house renovations. We help homeowners on fixed rates with time to run, those coming to the end of a deal and those whose homes need work before a standard mortgage is possible. Home improvements are one of several reasons to raise money against a home, and our page on how to release equity from your home compares them. The others have their own pages: debt consolidation mortgages, a remortgage to buy a second property and a remortgage for business purposes.

Home improvement remortgage rates

Home improvement remortgage rates are set by each lender on its normal remortgage range, by product and loan to value (LTV) band, and there is no separate price for improvements. Borrowing more raises the loan to value, and that can move the whole mortgage into a higher-priced band. On the illustration further down this page, £60,000 for an extension takes the loan to value from 57.1% to 74.3% of today's value. A further advance from your existing lender is priced on that lender's own further advance range and is usually set up as a separate part of the mortgage with its own rate, so the rate on your existing deal can carry on unchanged. A second charge mortgage is priced by the second lender, which ranks behind your first mortgage.

Besides the rate, a remortgage can carry a product fee and valuation and legal costs, although some products include them, and leaving a fixed or discounted deal early can mean an early repayment charge on the balance you repay. A further advance or a second charge leaves the existing deal in place, so the charge does not arise on it. Compare the routes on their total cost over the same period. Our page on fixed term mortgages explains how fixed rates are priced, and our guide to mortgages with no early repayment charge covers deals you can leave at any time.

Planning work on your home? Get in touch with the project cost, your home's value and your current mortgage. We compare the routes before the builder starts.

Home improvement capital raising criteria

Home improvement capital raising criteria cover the same points on every case, and each lender sets its own limits for them. The affordability and regulation rows rest on the FCA's rules and the Regulated Activities Order, checked in October 2026. The income multiple, term and credit rows are Mortgage Lane's experience on the cases we arrange. The other rows describe how lenders differ, and the lender's underwriting decides each case. In our experience the standard income multiple is 5 times income after credit commitments, up to 6 times for professionals and specialist products, and it applies to the whole mortgage after the extra borrowing, existing balance and new money together. A £400 a month car finance payment, for example, takes £4,800 a year off the income before the multiple, which on the illustration below lowers the most a lender might lend from £300,000 to £276,000.

Lenders set their own maximum loan to value for capital raising, and it can be lower than the maximum the same lender offers on a remortgage without extra borrowing. Some lenders ask for quotes, written estimates or a schedule of works above a set amount, and each sets its own threshold. Explaining what the money is for, with the quotes to hand, avoids questions at underwriting.

Past credit problems narrow the choice of lender. Adverse credit is assessed lender by lender on its age, size and whether it has been settled, and in our experience adverse credit lending usually stops at around 90% loan to value. Our pages on remortgaging with bad credit, CCJ mortgages, mortgages with defaults and mortgages with missed payments cover each type of entry.

Types of home improvement project, and how each is assessed

On a home improvement remortgage, lenders look at what the money will do to the property: non-structural work such as a new kitchen is usually straightforward, while structural work, a change of layout or a home that cannot be lived in draws more questions.

Extensions

Single and two-storey extensions add space, and often value, though the value added is not guaranteed. In England many single-storey rear extensions are permitted development: up to 4 metres deep on a detached house and 3 metres on other houses, no more than 4 metres high, and covering no more than half the land around the original house. Rear extensions of more than one storey are limited to 3 metres, side extensions of more than one storey need planning permission, and on designated land such as a conservation area all side extensions need it (Planning Portal: extensions). Householder permitted development rights do not cover flats and maisonettes. An extension is building work under the Building Regulations 2010, so it needs building regulations approval as well (legislation.gov.uk: Building Regulations 2010, regulation 3). A lender may ask for the plans, the approvals and the builder's quote, and it values the home without the extension until the work is done.

Get in touch with the plans and quotes.

Loft and garage conversions

Converting the loft of a house is often permitted development in England, subject to limits and conditions. These include no more than 40 cubic metres of extra roof space on a terraced house or 50 cubic metres on other houses, nothing higher than the existing roof, no extension beyond the roof slope at the front where the house faces a road, materials similar in appearance to the existing house, no balconies, verandas or raised platforms, and obscure glazing in side windows. The rights do not apply to flats or to houses on designated land such as a conservation area or National Park (Planning Portal: loft conversion planning permission). Building regulations approval is always needed to convert a loft into a liveable space, including a spare bedroom used only now and then, because the regulations cover the strength of the new floor, escape from fire, the stairs and sound insulation (Planning Portal: building regulations for a loft conversion). Wales applies the same requirement (gov.wales: building regulations for loft conversions). Converting a garage into a habitable room normally needs approval too (Planning Portal: garage conversion), and in Scotland converting a loft or garage into a room needs a building warrant. Lenders and future buyers will ask for the completion certificate.

Get in touch with the design.

Kitchens and bathrooms

Kitchens and bathrooms are smaller projects, often funded with a further advance or an unsecured loan rather than a full remortgage, especially while a fixed rate has time to run. A like-for-like refit does not usually need planning permission, and nor does moving internal walls. Taking out a load-bearing wall to open up a kitchen alters the structure, so it needs building regulations approval (Planning Portal: moving an internal load-bearing wall), or a building warrant in Scotland. Lenders treat a new kitchen or bathroom as a home improvement, and a lender may still ask for the quote.

Get in touch with the quote.

Energy-efficiency improvements

Insulation, heat pumps, solar panels and new windows can lower running costs, and they may improve the home's Energy Performance Certificate rating. Some lenders offer further advances or incentives for energy improvements, and what they offer, and on what terms, varies by lender. Check a lender's view of a measure before it goes in, because some spray foam insulation makes a home harder to mortgage or sell, as our page on spray foam insulation mortgages explains.

Get in touch with the measures planned.

Structural repairs and renovation

Roofs, underpinning and rewiring protect the home's value without adding space. The lender's valuation may pick up the defect, and where the home is in poor condition the lender can make a retention, holding back part of the loan until the repairs are done, or decline the case. Structural work needs building regulations approval, and a building survey shows what needs doing before you borrow. Homes in very poor condition may need refurbishment loans before a standard mortgage is possible, and on a home you live in that is a regulated bridging loan, which our guide to regulated bridging loans for homeowners covers.

Get in touch with the survey.

Which route: remortgage, further advance, second charge or personal loan

The cheapest route for a home improvement depends mostly on whether your current deal has ended and on how much the project costs. The sections below set out how each route works, and the table after them compares the five.

Remortgage with capital raising

A remortgage replaces your mortgage with a new one, from a new lender, for the existing balance plus the cost of the works. It suits a homeowner whose deal is ending or has ended, a larger project where the whole mortgage should sit on one rate, or a case where another lender offers better terms. The new lender values the home, checks affordability on the full amount and instructs the legal work. Leaving a fixed or discounted deal before it ends usually means an early repayment charge, so the timing is part of the cost.

Further advance from your existing lender

A further advance adds borrowing with the lender that already holds your mortgage. It is usually set up as a separate part of the mortgage with its own rate and term, so a fixed rate with time to run carries on and no early repayment charge arises on it. The lender still assesses affordability on the total and may revalue the home, and you are limited to its products and its loan to value limits. If the further advance is on a product that ends when your existing fix ends, both parts come up for the next remortgage together.

Second charge loan

A second charge loan comes from a different lender and is secured on your home behind your existing mortgage, so the first mortgage and its deal stay as they are. It can suit when your lender will not lend more, or when the early repayment charge on the main mortgage makes moving expensive. It ranks second in charge priority and is often priced higher than a remortgage or a further advance. A second charge on your home has been regulated as a mortgage since 21 March 2016 (FCA: PS15/9, the new regime for second charge mortgages), so the lender assesses affordability in the same way. Our page on second charge mortgages covers how they work.

Unsecured personal loan

A personal loan is not secured on your home, is usually repaid over a few years and involves no valuation or legal work on the property. It is consumer credit, a regulated credit agreement rather than a mortgage (legislation.gov.uk: Regulated Activities Order, article 60B). Unsecured lending to households has carried higher average interest rates than mortgages in the Bank of England's figures (Bank of England: effective interest rates, June 2026), but a shorter term keeps the total interest down. At the illustrative 5.2% used on this page, £60,000 over 25 years costs £357.78 a month and about £47,300 in interest, while over five years it costs £1,137.78 a month and about £8,300 in interest. Spreading a project over a long mortgage term lowers the monthly payment and raises the total paid, whichever product carries it. We compare a personal loan with the secured routes where it may suit a smaller project.

Refurbishment bridging

Where the home cannot be mortgaged until the works are done, a short-term bridging loan can fund them, followed by a remortgage once the home is habitable and revalued. The bridge needs a planned exit, and our page on remortgaging after a bridging loan covers that step.

Current value, then future value

Lenders lend against the home as it is today, so the money for an extension comes from existing equity, and the value the extension adds helps you only when the home is revalued after the work. The lender's valuer reports the value of the property in its present condition, and a standard lender lends a percentage of that figure. Plans and an estimate of the finished value do not change it. Some specialist lenders will consider the value after the works in limited cases, usually with detailed costings, but that is refurbishment or renovation lending rather than a standard remortgage.

Once the work is complete, signed off and revalued, the higher value lowers your loan to value. If that moves you into a lower band, a remortgage at the end of your deal can capture it. A product transfer with your current lender reflects the new value only if the lender agrees to revalue, and lenders differ on whether and how they do. Keep the completion certificate and any planning documents with your property papers, because the next lender's solicitor will ask for them.

The value added is not guaranteed: it depends on the local market, the quality of the work and the ceiling price for the street, and it can be less than the cost of the work. If the revaluation comes in lower than expected, the loan to value falls by less, and our page on a mortgage declined on valuation explains what a down valuation means for an application.

Planning permission and building control

Many extensions and loft conversions fall within permitted development rights, but others need planning permission, and almost all structural work needs building regulations approval. Planning permission decides whether the work may be built at all. Building regulations approval checks how it is built, including its structure, escape from fire and insulation. They are separate consents, and permitted development covers only the first. Listed buildings and homes in conservation areas have stricter rules, and a lender's solicitor, and later a buyer's, will ask for the approvals when you remortgage or sell.

England and Wales

In England, householder permitted development rights are set nationally, with limits on size, height and position that the Planning Portal sets out, and the rights are restricted on designated land such as conservation areas and National Parks. A council can also remove rights in an area with an Article 4 direction. Wales has its own householder rules and Welsh Government guidance (gov.wales: permitted development rights for householders), similar in outline but not identical. Where you are unsure whether work is permitted development, you can apply to the council for a lawful development certificate. The certificate confirms that proposed work would be lawful for planning purposes, but it does not cover building regulations or listed building consent (GOV.UK: lawful development certificates).

Building regulations approval comes from a building control body, which checks the work and gives a completion certificate once it is satisfied the work complies (legislation.gov.uk: Building Regulations 2010, regulation 17). Listed buildings also need listed building consent for works that would affect their character, separately from planning permission and building regulations, and carrying out such works without consent is a criminal offence. In England the requirement is in the Planning (Listed Buildings and Conservation Areas) Act 1990 (legislation.gov.uk: Planning (Listed Buildings and Conservation Areas) Act 1990, section 7), and in Wales it is in the Historic Environment (Wales) Act 2023 (legislation.gov.uk: Historic Environment (Wales) Act 2023, sections 88 and 89). For lending on them, see our page on mortgages for listed buildings.

Scotland and Northern Ireland

In Scotland, many small alterations and extensions can be made without a planning application, while work on a listed building can need listed building consent and work in a conservation area can need conservation area consent (mygov.scot: planning permission). Extending your home, converting a loft or garage into a room, removing a load-bearing wall and changing the roof all need a building warrant before work starts, and starting without one when it is needed is an offence (mygov.scot: building warrants). When the work is finished, a completion certificate is submitted to the council's verifier (legislation.gov.uk: Building (Scotland) Act 2003, section 17), and lenders and buyers' solicitors in Scotland ask to see the warrant and the accepted certificate. Our page on mortgages in Scotland covers buying and borrowing there.

In Northern Ireland, permitted development rights also allow certain works without planning permission, within dimension limits for extensions. Extending a flat or maisonette needs a planning application, and permitted development rights are restricted for listed buildings and in conservation areas and Areas of Outstanding Natural Beauty, so more works there need one (nidirect: planning permission, when to apply). Building regulations are a separate system, and you must tell your council about building work you want to do so that it can inspect and approve it (nidirect: building regulations approval). For the rest of the process, see our page on mortgages in Northern Ireland.

Work done without approval

Work done without the approvals it needed can hold up a remortgage or a sale, because the lender's solicitor reports missing consents and the lender may not proceed until they are dealt with. In England, the owner can apply for a regularisation certificate for unauthorised building work carried out on or after 11 November 1985, which may mean opening up the work for inspection. The certificate is evidence, though not conclusive evidence, that the work complies (legislation.gov.uk: Building Regulations 2010, regulation 18). Wales has its own version of the rule, and a council can ask for a retrospective planning application where permission was needed. Indemnity insurance is sometimes used instead. Mortgage Lane does not give legal advice, and a solicitor can advise on which applies to your property.

How a home improvement remortgage is arranged

1. Project and costs. Quotes, a contingency and a timetable for the works, with any plans and approvals. A 10% contingency on a £60,000 quote adds £6,000 and takes the loan to value on the illustration from 74.3% to 76.0%.
2. Route compared. Remortgage, further advance, second charge or unsecured borrowing, costed with any early repayment charge on the current deal and the fees of each route.
3. Application. An agreement in principle where the lender offers one, then the application, a credit search, the lender's valuation of the home as it is today and affordability on the new total.
4. Funds released. The mortgage offer, then completion, with the money usually released in one sum before the work starts.
5. After the work. Approvals and completion certificates kept, and a revaluation at the next remortgage.

Why home improvement applications are declined

The usual reasons are affordability that does not stretch to the larger loan, relying on a value the work has not yet added, an early repayment charge that makes moving uneconomic, applying to a lender that is cautious about structural works, and an unclear explanation of what the money is for. Each can be checked before you apply, and our page on a mortgage declined on affordability covers what to do after a decline.

An extension, before and after: the arithmetic

An illustrative homeowner with a £350,000 home and a £200,000 mortgage borrows £60,000 for a two-storey extension expected to lift the value to £420,000.

Step 1. Borrowing on today's value

The lender values the home at £350,000, as it stands, so the £60,000 is measured against that figure. The mortgage rises from £200,000 to £260,000, and the loan to value from 57.1% to 74.3%. The extra borrowing is priced at 74.3% because the lender uses today's value. Over 25 years, the £60,000 costs £357.78 a month at 5.2%, the illustrative rate used across our guides, which is not a product rate.

Step 2. Revalued after the works

Once the extension is finished, signed off and revalued at £420,000, the same £260,000 loan is 61.9% of the value. The table follows the homeowner's equity through the project.

Equity ends £10,000 higher than it started, because the extension added £70,000 of value and cost £60,000. If the revaluation came in at £390,000, the loan to value would be 66.7% and equity would end £20,000 lower than before the work. With no added value at all, the loan to value would stay at 74.3%.

Step 3. Affordability on the new total

The lender assesses the whole £260,000, existing loan and extra £60,000 together. Suppose the income the lender counts is £60,000 a year. At 5 times, the standard multiple in Mortgage Lane's experience, the most a lender might lend is £300,000, which leaves £40,000 of headroom. A £400 a month car finance payment comes off that income first, and the figure falls to £276,000, still above the £260,000 total.

Step 4. When the deal ends

At the next remortgage the loan is measured against the £420,000 value, so it is 61.9% in place of 74.3%. Lenders price in loan to value bands and each sets its own, so whether that is a lower band depends on the lenders available at the time. A further advance on a product that ends when the existing fix ends keeps both parts aligned, so the whole mortgage can be moved or switched in one step on the new value.

What decides the case

Fund the work from today's equity by the cheapest route given your current deal, counting any early repayment charge and the fees of each route: while a fixed rate has time to run that is often a further advance, or a second charge if your lender will not lend more, and when the deal is ending it is often a remortgage. Keep the approvals and completion certificates, and plan a revaluation for when the deal ends, without relying on the value the work might add. Our page on releasing equity from your home sets out the same routes for other purposes.