I thought I would add a few notes on here expressing my own views regarding the benefits and disadvantages of camper vans built with the double floor concept. First of all what do we mean by double floor? Well this is where the manufacturers build their campers using a raised floor on the inside, or encase the chassis in some cases to give usually around 27 to 30 cms (approximately one foot) space between each flooring. This allows all the fresh and waste water tanks together with its associated valves and pipework to be fitted in between the two floors.
Benefits. The benefits to this concept is that the tanks etc. are insulated from the outside and give a degree of protection from frost. Other benefits give the interior floor a flat and uncluttered area. Many of the higher end models of camper vans also fit the Alde wet central heating system that also fits inside the double floor and routes the heating pipes inside the floor so that in winter the pipes and tanks are constantly heated again preventing them from freezing. Camper vans with the blown air heating systems also route their pipes through the double floor to give a similar benefit.
Disadvantages. I guess the downside to this method of construction is that their may be a weight penalty leading to a reduction in available payload. Personally I believe that any small increase in weight is more than offset by the comfort factor of being able to use the camper in the depths of winter without fear of not being able to empty the waste water. Another downside may be an increase in the overall height of the camper though manufacturers such as Dethleffs, Burstner and Carthago all offer low-line models that are sub 3.0 mtrs yet all retain their double floors.
British Standards. Most British manufacturers of campers work to THE NCC EN1646-1 THERMAL INSULATION AND HEATING GRADE III CLASSIFICATION. They will claim Grade 3 classification is the highest standard for both insulation and heating, such that the interior of the Motorhome can be kept at +20°C when the external temperature is -15°C. The key word here is INTERIOR.
What this DOES NOT take into account is any pipework etc. that is OUTSIDE the habitation area – for example any underslung pipes, tanks or valves. It is mainly referring to the camper heating system in the habitation area to be able to maintain a temperature inside the camper to 20C. Any fool can work out that if you have a given volume to heat it is the output of the heater that will determine how hot the inside can be maintained. I accept that its not that simple and other factors are taken into account but I’m sure you get the point here. In my opinion this standard is partly irrelevant when you use the camper for real in winter. While it is true you want to be warm and toasty but this is not the whole problem. I believe this classification should be re-worded to make it clear that it refers to the inside of the Motorhome in regard to personal heating and does not include any external mechanical systems.
Many of the cheaper end of the European market don’t offer double floor models and neither do most of the British manufacturers with the Swift Kontiki range being the only exception at this time. Manufacturers that don’t offer double floors do tend to provide some form of insulation such as lagged pipes or heating elements that fit inside the waste and fresh water tanks. Its not the tanks freezing that causes problems in my experience – its the valves and associated pipework that freezes. We have seen numerous British camper vans with frozen pipes yet their tanks have been fine. This was no benefit to these poor souls as they could not empty their tanks simply because the valve was frozen or the drain pipe was frozen. Sadly it is my experience that the majority of British built vans don’t bother to insulate their pipework but merely offer tank heaters as an option.
Over the past 10 to 15 years more and more owners have been extending their holiday periods to include winter camping. This is evident when you see how many Caravan Club and Camping and Caravan Club sites are now open all year. This is the same all over Europe where we have encountered full camping sites and Aires in January and February. Indeed in Winter 2012 when there was freezing temperatures in February at Gruissan on the Med we counted more than 70 camper vans – many more than we saw in September the same year. Many of the ski resorts cater for camper vans these days so insulation is and will become more and more important. Even in UK there are many sites with 30 or more campers (and caravans) parked on club sites.
My simple advice to all is to take whatever precautions you can to protect your van if you intend to use it during the winter months. If not then remember to completely empty all tanks and leave the valves open. If you do intend to use your camper in winter then I would strongly advise you to take some precautions if you don’t have a double floor system. Lag all exposed pipes and valves, particularly the waste pipes (as you can normally get water in but not get it out) There are several ways to do this –
1. Use quilted hessian strips available from any plumbing merchants. Polystyrene pieces from DIY shops also help. Sheet foam can easily be stuck to the exposed surfaces of tanks and pipes. Use cable ties to hold them in place.
2. Some specialist firms offer low wattage 12 volts heating wire strips that can be wrapped around exposed pipes that can be controlled either by a simple on-off switch manually or automatically by thermostat that turns on when the temperature drops below around 5 degrees centigrade. Do be careful regarding power usage as you don’t want to leave them turned on for too long and risk flattening the leisure batteries.
3. Lagging the gas regulator (if it isn’t a heated one) can also benefit as even the smallest amount of water in a regulator can cause it to freeze and give the symptom of an empty tank (it happened to me so my ramblings on LPG)
In conclusion it all comes down to cost, style and in particular the time of year you use your camper van. If you stay at home during the cold winter period or you only have a few weeks a year off work then I guess insulated pipes and valves are not at the top of your list. However if you do want to use your camper all year round then exterior insulation is important. While double floors cope better in winter a few simple precautions to protect external fittings will help prevent hardship. Finally the existence of a double floor should not be regarded as an end to the matter as even campers with double floors can come unstuck. As an example we were parked next to a top of the range Frankia with a double floor however his waste valve was external to his double floor and so froze overnight. He said he would be lagging this as soon as he got home…….