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Are BISF houses safe? How long do BISF houses last?

Out of all the breeds of non standard construction, BISF houses are one that you can't afford not to have on your radar.

Why? Because they're not like your typical property. Neither are they something you can afford to confuse with your average home.

You see, over a period of 6 years, more than 35,000 of these 'problem properties' were built across the UK!

That's the equivalent to half of all the households in York! And yet, BISF houses can't just be found in one place. You'll find them scattered all over the country, everywhere from Yorkshire and Humberside to parts of the Midlands and the south.

Therefore, being clued up on what they are as well as their shortfalls isn't just a good idea - it's essential. Fact remains that BISF houses aren't the most popular houses out there, and that there's good reason for it.

We should know, as we often buy BISF houses for CASH! So, with this in mind, are BISF houses safe? And can you use a house repayments to buy a BISF house? We reveal all...

Searching for something specific about a BISF house? Or just curious as to what one is? Use the menu below to find the answers you need fast...
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What is BISF steel construction?

A BISF house (otherwise known as an Airey house) is a property built around a steel construction, which can often be referred to as a prefab home.

Reason for their two nicknames stems back to how they were built; the most popular design was the product of engineer, Sir Edwin Airey, which was manufactured by the British Iron and Steel Federation.

Buy a BISF house and it was probably built in quick succession after the second world war.

Being prefab, a BISF house comprises of panels built in a factory, which are assembled in panels on-site. Basically a flatpack house - call it 1940s Ikea.

Although, the reason for their construction was simple: to satisfy housing demand, at a time when raw materials were in short supply.

So as you can imagine, when compared to your standard home, a BISF house doesn't bear much in the way of similarities. It's anything but ordinary.

Therefore, to help you get your head around the differences, here's a few ways you can easily spot a BISF house...

  • The absence of a porch. Unless a BISF house has been modified, there isn't usually a porch. Instead outside coverage is limited to an external canopy, held up by two metal posts. A stand-out feature of most BISFs.

  • Their construction isn't conventional either. Unlike your standard property, a BISF house isn't made of brick. In fact, there isn't even one brick used in its entire construction. Concrete panels known as ship-lap make up its exterior. Panels which are reinforced by metal tubing.

  • Small and pokey windows. On a BISF house the windows aren't exactly a stand-out feature. As Airey houses were designed to be functional, there's none of the extravagant glass work that you'll find in something Georgian, nor the grandeur of something Victorian. The windows are merely designed with one thing in mind... to be windows. That's it.

  • The fact they're a struggle to finance. This is because today, BISF properties are listed as part of the Housing Defects Act (1985). All of which means that many lenders aren't all that keen to lend and that when buying a BISF house, specialist finance or cash is the way to go.

Are BISF houses safe? How long do they last?

Yes, of course BISF houses are safe.

If BISF houses weren't safe then we're pretty sure that people wouldn't still be living in them and home insurance providers would be denying cover to every BISF owner out there (not true).

In fact, the safety risk with a BISF house is much the same as with any property.

The roof might get damaged in a heavy storm, it could subside if the ground below becomes unstable or get flooded if it's been built on a floodplain.

The only real threat to safety comes when a BISF house is neglected and its upkeep is put on the back-burner.

Being a slightly more niche type of property, this is where BISFs and standard brick-built properties begin to differ.

Neglected BISF houses require specialist attention, which as you'd guess, doesn't come cheap. In the event of something major, they may also require bespoke panels to be remade or one-off components fabricating from scratch. Yet another scenario where costs could escalate.

And it's also worth remembering that any BISFs still around today, are only going to be around 70 years old. Now, while Georgian and Tudor properties have proven that homes can last well over a century, it's worth remembering that these were stone-built, not made of concrete.

A material that let's be honest doesn't have a great reputation when it comes to building houses - it's still yet to outdo the bricks and mortar.

So while BISF houses are safe providing they're well-looked after, just like new Bellway boxes, for how long is really a mystery. Give it 50 years or so, and we may find out.

TIP: Selling a BISF house? Be sure to keep ALL the receipts for any work you've had done. Proof that you've spent a decent sum of money keeping up to the property can really go a long way when it comes to winning a buyer's confidence.

You could even take before and after photos while the work is being done if you want extra proof!

Why wait on the open market?

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Can I get a mortgage on a BISF house?

Indeed you can. While mortgages for a BISF house are hard to come by (as many owners will know), they're by no means impossible to get.

As with all mortgages, how mortgageable a BISF house is all comes back to reliability.

You see, the reason getting a mortgages on a BISF house can be such a challenge is because of their somewhat scarred reputation; BISF houses appear on the Housing Defects Act (1985).

All of which makes insurers a good deal more tentative about lending, as through their 'risk orientated' spectacles, BISF houses can be a red flag. However, saying that, there are a few precautions that you and your buyer can take to up the chances of approval. Here's a couple to consider...

Tips for sellers

Flash the guarantees

Because lenders (just like insurers) are all about risk, putting their doubts at ease is essential. A chore that surprisingly isn't as hard as you think!

Just had some work done to your BISF house? Keep the receipt and give potential buyers a copy to send out to lenders, especially if the work comes with some form of guarantee. The more assurance the lender has, the more mortgageable your BISF house is likely to be.

Reinforce your BISF house

On the subject of home improvement, sellers who own a BISF house that isn't selling on the open market, may wish to go the extra mile and reinforce their property.

This is usually done with brick. Do so and what a lender sees is essentially an extra layer of security. A bonus that could see them be more open to lending on higher LTVs.

Tips for buyers

Lower that LTV

When trying to secure a mortgage on an Airey house, deposit is crucial. The lower it is, the less risk there is on the lender, so it's understandable why having a large deposit, can sway lenders in your favour.

Persuade a buyer to change their LTV from 80% to 50% and you'll stand a far better chance of coaxing a loan out of your lender's back pocket.

Provide back-up

Now, it's fair to say that not every buyer will be able to put down a 50% deposit - but even then it's not the end of the road! Buyers who've got their heart set on your BISF house could back up their purchase using a guarantor mortgages, or some other form of guaranteed finance.

In the case they have a second home (perhaps a buy to let), there's also a good chance that they could use that as collateral too. A move that's more than likely to tip the tables.

BISF house renovation: Is it possible?

Indeed it is.

In fact, renovating a BISF house is a great way to make it more saleable. Reason being that not only does it assure buyers of its build quality, but it also increases a lender's trust in your property.

Therefore, for any potential buyers, fears about securing a house repayments are likely to be far less. Home insurance should also be much easier to secure too. And as you can probably guess, with that should come an increase in the core value of your home. The only catch is that all this renovation doesn't come cheap.

A full renovation of a BISF house can stretch to several thousand pounds, maybe even touch on 10s of thousands, depending what spec you opt for.

But, what exactly is BISF renovation? Here's just some of the options you'll be able to pick for when specifying a BISF renovation...


By far one of the most effective ways to upgrade your BISF house is with cladding. Arguably the easiest way to disguise its BISF heritage.

Something that will almost certainly pay dividend when listing it for sale on the open market. In most cases a clad is all that's needed to give a BISF that visual lift it needs to sell.

Plus, it's fully customisable too. Clads themselves come a whole variety of colours and textures, with traditional stone and red brick being some of the most popular.

Plus, if you're feeling creative, you can even mix clads too. A plain clad on ground level and a brick clad on any upper storeys is a popular way of creating a more traditional aesthetic.


Another tell-tale sign of a BISF house is its roof, which due to it being a prefab home, has to be lightweight; a heavy roof could severely compromise the structure of a BISF house.

Hence why the majority of BISF houses will boast some for of metal or asbestos roof. But now, thanks to improvements in technology, BISFs can be upgraded with lightweight interlocking systems that more or less imitate a traditional roof, as well as retain most of the perks.


A distinguishing feature of a BISF house is its canopy, which you can usually tell because of how it's held up by two metal posts.

However, that's not to say you can't change all that. You see, another way to facelift your BISF is by fitting it with a free hanging canopy that's fixed above your doorway.

Besides, with enticing entrance way, you'll be far more likely to entice buyers inside. Not bad for a relatively minor home improvement.

PVC windows

One bug bear of a BISF has always been its windows. It's often said they're small, pokey and being single hardly ideal when it comes to keeping the house warm.

Switch these out for PVC glazing however and you could soon see your EPC rating rise, especially if you time your replacement with a new roof too!

Thanks to their metal construction, BISFs are notoriously hard to heat, which is why improvements like this can really boost their saleability. Saying that though, this option isn't cheap.

FYI: Before commissioning a renovation it's also worth double checking for any asbestos in areas besides the roof.

Sadly, it's thought to be used in the construction of many post-war prefabs, including BISFs, in areas besides the roof. So do your research before commissioning a BISF renovations company.

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BISF house pros and cons explained

As with most types of houses, BISFs a good deal as pros, as well as their fair share of cons too. And this is why when you come to sell that you'll be hunting for a very specific type of buyer. One that's perhaps not afraid of a project or taking a risk financially.

Reason being that one of the major quibbles with BISF houses is the risk that comes with them. So, to help you weigh up both sides and see the BISF house through your buyer's eyes, here's a quick rundown of the pros and cons that you need to be mindful of when selling a BISF house...

Pros of a BISF house

BISF houses are almost always cheaper to buy than an equivalent brick built house.

Good news if your goal is to outprice similar houses in your area and tap into their pool of interested buyers.

Letting a BISF is practically no different than renting an average brick-built home, so the yield for investors tends to be a LOT higher.

Yes, they might be slightly harder to get tenanted, but in terms of monthly rent, as an owner you shouldn't have to take a cut.

Even if a BISF is a bit worse for wear, it'll likely be a better position than most newbuilds, which tend to be built further out of the city centre.

Therefore, the land value is likely to be more. Something to bear in mind if you get any developers making cheeky offers.

Cons of a BISF house

For a lot of replacement parts or advice, you'll need to go to a specialist, which as you can imagine, comes at a premium.

What's more, the amount of BISF specialists in the UK isn't all that large, so you'll likely be shoehorned into using a certain pool of companies.

BISF houses are notoriously hard to get a house repayments on - there, we said it. As a result, when you come to sell your pool of potential buyers is likely to be rather slim.

In other words, it's likely that you'll have to wait it out for a fair bit on the open market before one comes along. Usually, this'll be a developer who's after the land or a cash-ready buyer like ourselves.

Due to the construction of a BISF house, running costs (in particular, heating), can set an owner back a fair bit when compared to the more modern alternatives.

The equivalent for instance, will likely be better insulated and come with far more in the way of energy-saving tech.

What's the best way to sell as BISF house?

Now that's a tricky one.

You see, you could sell a BISF through the open market - the traditional route that'd likely be your first port of call when selling a house.

However, with a BISF house that's going to be tad difficult. Reason being that by selling on the open market, you are much as it sounds, putting your house out there to whoever appears to be looking at the moment.

Only trouble is, very few of these buyers are specifically on the hunt for a BISF house. The majority may even avoid them full stop.

So, what that means is that you're essentially marketing your property to a mass of (to put it politely) uninterested buyers.

Buyers that aren't going to show much in the way of serious interest, which is only going to eat up a good chunk of your time and money.

Ask us and when selling a BISF house you need a different solution.

One that's fast, straight-forward and guarantees you a sale whatever your BISF's condition or location.

Sound appealing? Well you may be in luck...

As an industry leading cash buyer of property, we'll buy your BISF in as little as 7-days! Yes, you read that right.

What's more, our team has well over 50 years' experience in the area of buying houses for CASH.

We're also a reliable bunch too. As of writing this blog, we score a whopping 4.7 out of 5 on Trustpilot - can't argue with that.

PS: As a special thankyou for selling your BISF to us, we'll even cover the cost your solicitors and surveys too!

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Joe McCorry

Joe is our SEO Specialist that helps produce and develop content. He enjoys finding out about all the new property trends and learning about the property market.