Park Home floor insulation – facts and fallacies.

Tingdene Homes have a lovely square chassis, always a pleasure to work below their homes!

You may have insulated your walls and roof, but your feet still feel cold. It’s time to think of the amazing benefits of Park Home floor insulation. Choosing the right materials and the right Company to fit it is a minefield, so here’s some information to help you make that choice.

Many refurbishers refer vaguely to ‘new systems’, wonderful new lightweight technology and the ubiquitous ‘Superfoil’ or ‘Double Bubble’ quilt type insulation.

Back to school

Going back to school – I know, I know, for the vast majority of us, a long time ago – but you may remember the following facts from the Physics teacher about heat transfer:

Three types: Radiant, Conduction and Convection. The full info here from the good old Beeb if you are of a scientific bent:

In layman’s terms, Radiant means reflection (eg light/heat bouncing off shiny surfaces), Conduction means similar material up against similar material (eg metal to metal) and Convection means cold air replacing hot.

Which insulation keeps you warmer?

‘Superfoil’ and other double-bubble insulation is only good at combatting Radiant heat loss. It does not combat Conductive nor Convective heat loss effectively. The material is too thin. The material usually poorly fitted by cowboy installers (ie edges not sealed and run over pipes and wiring and sometimes even the chassis!)

Typical cowboy fitting of ‘Superfoil’ or ‘double-bubble’ under a home.
No sealed edges, gaping holes, poor fitting, no care taken.

Loft Roll (eg glass fibre, rockwool, sheep’s wool etc) is only good at combatting Conductive heat loss. It does not combat Radiant nor Convective heat loss effectively unless combined with a reflective layer. Insulation must be sealed tight and be fitted at an even depth below the home. This is rarely possible due to it being slung between the floor bearers (joists) and held up by netting or a moisture barrier.

The only completely effective Park Home underfloor insulation is PIR Board. It combats Radiant heat loss due to the foil backing on both sides, it combats Conductive heat loss due to the non-conducting foam construction and is gas-tight due to the closed-cell construction (ie it won’t let air through.)

PIR Board makes are those such as Recticel, Celotex, Xtratherm, Ecotherm, Kingspan, Quinntherm etc.

The right materials still need fitting correctly

Now, though PIR Board is the best material for below Park Homes, full effectiveness relies on the following:

1. The thickness of the board.
2. The quality/method of the fitting.
3. The type (manufacturer) of board.
4. The measures taken to combat ‘Thermal Bridging’ or ‘Cold Bridging’.
5. Gas Safety and the importance of ventilation.
6. The importance of the moisture barrier.

1. Board Thickness.

There are calculations and all sorts of scientific equations (eg ‘U’ value and ‘R’ value) made to specify what thickness of board is most effective and there are strict rules governing depth/thickness of board required in New Build Bricks and Mortar regulations.

Thankfully, we don’t have to stick to those when fitting aftermarket insulation below Park Homes otherwise it would take an age to fit and cost you the earth!

Suffice to say the thicker the better and more effective – ie you will feel warmer and be turning down your thermostat several degrees. Conversely, in Summer, you will feel cooler because the heat below your home will be kept out of the House by the ‘thicker’ insulation.

The vast majority of Park Home underfloor insulation contractors that use PIR Board use 25mm (1″ in old money) board. Some claim to use 30mm – and indeed charge for it – but they don’t, reckoning that you won’t be out there with a tape measure checking for the 5mm difference!

We use 40mm (1 1/2″) Board as standard, but will fit 50mm (2″ in old money) if you wish. Like any insulation though, the effectiveness is in the fitting. You can fit 100mm (4″) but if it’s fitted badly it’s no better than 40mm fitted well!

2. Quality/Method of Fitting

Proper care when fitting brings the best results. Park Homes are a unique challenge to the installer due to the steel chassis, the pipework and the wiring that run below and above an insulation fitment.

This means that cut-outs have to be made around these obstructions. All gaps must be filled and all joints must be sealed in order to make the fitment as air tight as possible. This combats Convective heat loss – that is the ‘sucking-out’ of the warm air and replacement with cold air.

Our attention to detail saves you money.

We use foil tape to seal the joints and cut outs. Some contractors use Expanding Foam to seal the joints/cut outs. It’s quick for their fitters, but will lead to expensive repairs should you need plumbing or electrical work under your home in the future. Many fall for it and regret it later.

Look at the mess. Try removing and replacing that if you’ve a problem below your floor.

3.  Type/Manufacturer of Board

We’ve tried and tested all the major manufacturers. In spite of the manufacturer’s claims, we have found only two makes of boards that are suitable below a Park Home. Every other type of board has split or curled away from the fixings.

The two types of Board that we use are Recticel and Ecotherm because of their rigidity, resistance to curling/splitting and their durability.

Many other boards degrade quickly as well. Take a stroll down the insulation aisle of a B & Q or a Wickes and have a look at the state of the boards in those aisles. Yellow/orange sides and lumps missing.  Do you really want that board under your Home?

4.  Combatting ‘Thermal’ or ‘Cold Bridging’

The unique challenges of insulating a Park Home are legion! It’s not easy to get a good fit at the sides above tight brick skirting. The steel chassis is an excellent conductor of heat and cold, so I describe it loosely to clients as a ‘dagger of cold into your warm space’.

100mm (4 inch) wool lining the steel chassis to combat thermal bridging.

We get around this by isolating the chassis with 100mm recycled wool or Rockwool Flexi. The material also acts as a barrier, so that if the insulation is breached or damaged subsequently, there will only be one cold spot. No thermal bridging material fitted halves the effectiveness of insulation.

5. Gas Safety and the importance of ventilation.

Mains gas is lighter than air, so therefore will rise. As long as you have plenty of ventilation in your walls and windows,  you won’t have a problem should a gas leak occur. LPG (Liquid Petroleum Gas) is heavier than air and will collect at the lowest point.

Residential Park Homes with a LPG supply, whether through Gas Bottles or piped from a tank MUST have Gas Safety drop-down holes fitted in the floor at every pipe entry point.

This means that if there’s a gas leak in the Home, the gas will drop through these holes into your crawl space and disperse safely through airbricks.

We fit LPG gas drop-down holes as a matter of course during an Insulation fitment. We know that other underfloor insulation firms don’t because we’ve seen their work. and had to insert drop-down holes for worried customers.

Drop-down LPG gas escape below a refurbished Donnington Castle single unit.

Ventilation below the Home is crucial. Airbricks must be fitted on the bottom or first course of any brick skirting for LPG gas dispersal. Many bricklayers are ignorant of this fact and place the airbricks halfway up the skirting or at the top, even on new Homes. We fit correctly positioned airbricks where the ventilation is poor or the bricks have been fitted incorrectly.

6. The importance of the Moisture Barrier

Some Park Homes have a Vapour Barrier, some have a Moisture Barrier fitted below the floor.  Some older Park Homes have no barrier at all. Those early homes were not intended to last as long as this.

A Vapour Barrier is to stop low concentrations of damp rising up through your floor. A Moisture Barrier is to stop heavy concentrations of damp rising up through your floor.

A repaired moisture barrier before insulating.

Left unchecked, rising damp from below the Home (eg flooded base, leaking pipes, overflowing rainwater barrels, undiverted rainwater) can destroy your flooring and lead to mould and fungus on your lower walls. This is a definite health hazard along with causing spongy floors and ill-fitting laminate flooring.

We repair torn/missing portions of moisture barrier and fit entirely new where none exists. Anyone insulating below a floor with no moisture barrier is asking for future trouble, and possible extensive floor repairs in the future.

In conclusion, there is definitely a right and a wrong way to insulate a Park Home floor. The trouble is, you won’t find out that you’ve chosen wrongly until some years later.

This isn’t a scientific article. Hopefully you can now make an informed choice for a major upgrade of your insulation. Don’t waste money on poor materials and poor workmanship. Don’t take the Salesperson’s word for it, do your research.

If you’ve enjoyed reading this and would like a quote for your floor to be insulated properly, email us on

Park Home Underfloor Scams and Lies.

The ‘Floor Bounce’ scam

The ‘Surveyor’ or ‘Salesman’ is invited into your Home to test the floor. He’s a big chap, finds the least supported part of your floor (usually the middle of a unit, not the centre-join of two units) and proceeds to jump up and down on the floor. Consequently the furniture moves, the windows rattle and ornaments fall over.

‘Your Home needs full re-support.’ says he, and the poor householder falls for it, when usually, it’s only the coach bolts that need tightening or most probably nothing wrong at all.

A 17 stone bloke jumping on a wooden floor is always going to cause problems.

The ’Got some jacks left over’ scam

No 1. The doorbell goes, a chap tells you they have some jacks left over from a job. Do you have any creaks coming from your floor? Would you like them to put them under your home?

I would say 100% of Park Homes have a creak or two. It’s a timber framed home and creaks will come and go with the weather. I live in a bricks and mortar house and the stairs and upstairs floors creak like crazy. You’ll pay well over the odds for Supports that you don’t need. Don’t fall for it.

No. 2. The doorbell goes, a chap tells you they have some jacks left over from a job. Do you have any creaks coming from your floor? ‘Look’ says he, ‘we can’t hang about, we’re due at another job. What we’ll do is you pay for them now, we’ll leave them here and come back later to fit them for you.’

Of course, you’ll never see them again …

We use a ‘rust-inhibiting paint.’

 Why not say which paint you use? We only use Hammerite – and we say so. They’re using a cheap and cheerful metal paint or even primer, which is no use unless it’s covered with a top coat. Ask what you’re getting or you’ll end up having to have it done again a couple of years later.

The ‘only paint near the hatch’ scam

You have engaged a Refurbisher to paint your chassis. They’re under there for a couple of hours, finally reappearing to say ‘All done. Would you like to check our work?’ They know the vast majority of Park Home residents are either incapable or unwilling to go under the Home to check – and they certainly don’t offer you photos of what they’ve done. So, you kneel down at the hatch and look under. Yes, it’s a wonderful job – NEAR THE HATCH – but completely untouched elsewhere.

The ‘it’ll cause more problems levelling the Home than leaving it as it is.’ scam.

This is the ‘get-out of work they can’t do’ lie used by the self-proclaimed and heavily-advertised ‘leading underfloor refurbishment company’. They claim they do it on their web sites and advertising but when they’re surveying/estimating they’ll tell you it can’t be done. Rubbish. Every Park Home can be levelled – even homes with added porches and conservatories. They want your other easy work, so they lie to get out of work they can’t do.

The ‘miracle superfoil’ or ‘bubblewrap’ underfloor insulation scam.

It’s ALWAYS poorly fitted, the edges are never sealed, it’s loose around pipework and wiring and it’s a ‘cowboy builders’ dream. There’s no prep needed, it can be fitted in a couple of hours, and again, it always looks great near the hatch. You’d be better off lining the floor with Bacofoil. Save up or take a loan out to have it done properly otherwise you are just wasting your money.

 The ‘distorted survey’ scam.

You engage an Underfloor Company to survey beneath your home. 99 times out of 100, they will report that the chassis needs refurbishing and the supports need replacing. What they won’t tell you about are the other problems the Home may have – eg cracked base, poor plumbing, worm or rot in the floor bearers and the Home out-of-level. They won’t tell you because THEY DON’T DO THAT KIND OF WORK!

The Surveyor who likes backhanders.

Many new buyers of Park Homes are green as grass. Many don’t even realise the Park Home is built on a wheeled chassis. Seeing a brick skirting, many folk think the home has a solid brick base. The sensible ones have a Survey carried out. Unfortunately, some of these Surveyors go out of their way to criticise the state of the chassis when the vast majority of Park Home steel chassis’ will see us all out, rusty or not. So they rubbish the chassis and in their notes put the contact details of the underfloor refurbisher that gives them a £50 gift (or bribe) for every lead.

The Surveyor who hasn’t a clue.

This is a proper scandal. The biggest (and I mean THE biggest) outside Refurbishment Companies have Surveyors that are experts on roofs, walls, windows, but have not got the first idea of the underfloor area of Park Homes. They tell you that everything is fine below the home and go on to sell you £10, 20, 30 grand’s worth of work to the outside. So you go ahead with the work only to find out in the future that the Home’s out-of-level, poorly supported, the sides of the home are drooping because there’s no support at the sides for the added weight of new roof, walls and windows that the original home was not designed for. Try selling that in the future – unless of course you engage this chap …

… the Surveyor who’s working for the Park Owner

You engage a Surveyor to examine the Home you’re  buying. He reports that the underfloor area is fine or that there’s one or two minor problems. What is actually happening is that the Surveyor is hand-in-glove with the Park Owner. The Park Owner wants the home sold and for a top price. If there’s no problems, the Park Owner gets 10% of a top price. If there’s problems and the selling price is reduced, the Park Owner gets a reduced 10%, so therefore, it’s in his interests to give the Surveyor a cash backhander to overlook problems below the home. The Seller’s happy, the Park Owner’s happy, the Surveyor’s happy but the new owner has been robbed blind and may end up with an unsalable home or expensive problems in the future.

Thinking you’ve got yourself a good deal by paying cash.

Whoop-de-doop. You’ve saved yourself a few hundred by paying cash, rather than paying the VAT. The trouble is, you’ve got no paperwork, no invoice, no evidence that they ever did the work. If they’re willing to take a cash payment, they’re dishonest and the work is going to be very poor quality. You’ve got no comeback if there’s problems, and you’re also an accessory to a fraudulent transaction.

Customs and Excise are no fools and any examination of a Company’s records will find a discrepancy – eg materials bought on the day near your Park, with your name and address in diaries and appointment books and your number on phone records.

Glowing testimonials by Customers that haven’t got a clue …

 ‘Oh they were so quick!’

They’ve rushed the work. No proper prep, a quick cosmetic job. In and out in 6 hours and it’s just cost you £2500.

‘Oh they were so clean!

The outside may well be spotless, but underneath, the base  still looks like the fly-tipped rubbish depository it was when they first started.

‘We were kept informed throughout the job.’

Indeed you were, but only about the things they can actually do. You weren’t informed about the things they can’t or won’t do.

‘They did a wonderful job.’

How do you know? They’ve provided no photos of what they’ve done.

A Clean Bill of Health?

It’s no secret that the vast majority of Park Home residents are Senior Citizens (or Pensioners in old money.) How wonderful to not be subject to the daily commute and treadmill. The downside for some though is to be dogged by health problems.

Many residents suffer respiratory diseases – coughs, colds, asthma and for ex and current smokers, emphysema.

Why Park Homes can be bad for your health

Google will turn up many articles on damp and mould and the effect on air quality in the traditional home. You’ll find very little relating to air quality in Park Homes.

Now, I’m no Scientist – I managed to get Biology ‘O’ Level, but failed miserably with Physics and Chemistry! I have a PhD in the University of Life or the School of Hard Knocks as it’s sometimes known. Years spent diagnosing and fixing problems beneath Park Homes however, gives me an advantage over the Scientists!

Many Park Home residents are suffering because they are living above what can only be described as a swamp. A crawl space contaminated with rubbish, debris, dried effluent and standing water.

How standing water gets under your home

Kitchen/Bathroom/Washer/Dishwasher wastes or soil pipes leaking or broken.

Mains or hot & cold feed pipes dripping/leaking.

Rainwater leaching through brickwork.

Where the home’s base is lower than the surrounding landscaping.

A poorly-maintained crawl space is a health hazard

A modern Park Home will have a moisture barrier and insulation below the floor. A torn moisture barrier and missing insulation allows damp and cold into the home. An older home may have neither moisture barrier nor adequate insulation. Older homes with new fitted bathrooms and kitchens will be poorly finished below. I have yet to meet the Plumber who replaces barriers and insulation when he’s finished. Out of sight and out of mind.

Black mould on the skirting and lower walls indoors or inside cupboards and wardrobes is an obvious warning. Damp carpets and spongy floors are further signs. You have standing water below the home and it’s a health hazard.

A welcome mat for vermin

A crawl space covered in muck and debris holds the water in. It makes drainage and evaporation very difficult. Once you have this situation, it rapidly attracts rats and mice. The patter of tiny feet in the walls, roof or below the floor is a warning sign.

The presence of vermin in your crawl space is not conducive to good health for Park Home residents.  The damage they can do to your plastic plumbing, insulation and moisture barrier can also be costly.

Get it cleaned!

A clean, dry and well-maintained crawl space is an essential first step to better health for Park Home residents. Ask your Doctor or other Health professional if this would be beneficial to your health. Call Environmental Health at your Local Council if you suspect problems below your Home.

Let us do it for you!

We’ll clean out the underfloor area, dispose of all rubbish and rectify damp and flooding problems. Bite the bullet and you’ll feel the benefit this winter!

Email us at

for a Survey/Inspection and let us set your mind at rest.

Should I have my Park Home Surveyed?

There still appears to be a laissez-faire kind of attitude to Park Home Surveys. I find this quite incredible.

Now look, I know a little bit about cars – I used to own a Triumph GT6 Mk II and if you’ve ever had to change the rotoflex couplings on one, you’ll know where I’m coming from – and have done the vast majority of the maintenance on the succession of vans I’ve owned ever since. However, I wouldn’t even buy a £2k runabout without having an independent inspection carried out on it.

Out there in Park Home Fantasyland, you’ve got folk paying out vast sums for their dream retirement home. Some new Park Homes sell for £300k plus nowadays and even old single units reach £100k. It’s a tremendous risk to buy one  without having an independent £400-odd survey. Madness.

Get it Surveyed!

First things first, you should only ever buy any kind of Park Home after having a Survey. That includes new as well as old.

I’ve lost count of the number of folk who claim that they didn’t need a Park Home survey because they or someone they know has been in the building trade all their lives. There’s little comparison between bricks and mortar and Park Homes – even the common features of roof, walls and windows are completely different materials and construction.

Older folk can be con merchants too.

If you’re a buyer and fail to have a survey carried out, you are entering a possible world of pain, both financial and mental … and with some homes, possibly physical too! Just because the vast majority of Park Home residents are older folk does not mean that they are all sweetness and light and upstanding citizens … they’re just like the rest of us with the same proportion of good and bad and middling.

By that I mean that among the honest folk there’s the same ratio of bodgers, misers, conmen and cheats that are in the rest of society. So what might outwardly seem a beguiling purchase may not be what it purports to be. Without a Survey, you’ll never know until the problems start when you get to know the home.

Brand New Park Homes need a Survey too!

Why New Homes and Lodges as well? Surely they come with all sorts of guarantees and suchlike I hear you say. Indeed they do, but any new home could have underfloor faults that you wouldn’t even know about until years later.

Poor initial siting of the Home can lead to problems throughout the life of it.

Typical problems include:

  • Sloping/flooding concrete bases, cracks and splits in the concrete.
  • Homes neither supported nor levelled correctly.
  • Poor paint finish on the chassis.
  • Gaping holes in the moisture barrier/insulation.
  • Poorly lagged pipes, some pipes left unprotected.
  • Excess mortar and muck blocking airbricks and drainage points,  dirt and debris strewn throughout.
  • Water leaks from poorly fitted wastes, soil and sometimes feed pipes.
  • Extensive landscaping causing the base to flood.

A good Surveyor will find all these faults and you have the chance to have them put right at the Seller’s expense and headache rather than yours before you move in. You may be able to negotiate money off the sale for you to get any remedial work done to your complete satisfaction.

There’s a world of difference in having the Home and its’ faults (if any I hasten to add, there are folk who do a great job out there) sorted before you move in.

Once you’re in and you begin to find faults, you will have to play the old ‘Whose responsibility is it?’ game. Park Owner/Manager? Siters? Manufacturer? Gold/Platinum Seal Warranty? Estate Agent? Insurance?

I would imagine you’ve got better and more fruitful things to do.

Get it independently surveyed, old or new before you move in. You’ll thank me one day.


Park Home Surveys

If you’re just looking at an underfloor/crawl space Survey, contact us at

However, if you’re in need of a Survey for the whole Home, the site and its’ environs, we can thoroughly recommend Subject II Survey of Bicester.






Chassis Doctor Ltd

Hi and welcome to our Web Site/Blog.

We’re here to give advice to Park Home residents and to cut through all the nonsense and downright lies that most Park Home Refurbishers and Chassis Companies spout.

Based in Bedford, we cover Counties local to Bedfordshire. I’m too long in the tooth to be travelling miles now.

We’re not beholden to any Park Home Manufacturer, we don’t have any ties to Park Home Refurbishers, we don’t get kickbacks from anyone. We’re not members of any Industry back-slapping and price-fixing organisations and we don’t have any arrangements with Park Owners. We don’t advertise in the glossy magazines titled ‘Park Home this and that’ because they accept adverts from anyone with the money and carry out no background checks or assurances as to how qualified they are to do the work they’re touting for.

We’re completely – and proudly – independent.

If we recommend someone, it’s because we’ve seen their work and seen their prices.  There are plenty of cowboys in this Industry and we know who they are. This doesn’t only include the doorknockers  and ‘Rogue Trader’ conmen – some of the biggest rip-off merchants are among the best known names in the Industry.

What this means is that we work solely – and uniquely – for you. We’re not cheap, but neither are we expensive. We charge fair prices, use the best equipment and the best materials.

Our Underfloor Surveys are the best in the business. We won’t lie to you. If something needs doing, we’ll tell you and that includes things we don’t do – for instance, we’ll advise if you need an Electrical or Gas check – we won’t hold back for fear of ‘losing the job’.

We’re not everyone’s cup of tea and we accept that. If you don’t like straight talking, don’t call, simple as that.

OK, enough of the negatives!

We’re very, very good at what we do. Whether it’s a complete underfloor refurbishment to just a Jack replacement, we carry out the job with a high degree of professionalism and care.

We give full 10 year Guarantees on our work and photograph everything before, during and after the work so that you can see for yourselves exactly what we’ve done, and so you have a record to show prospective buyers if you ever come to  sell your home and the peace of mind of knowing that all has been carried out to the letter.

Email us today and put your mind at rest.