The importance of motorhome damp checks

Barring serious road traffic accident damage, water ingress is by far the worst enemy of your motorhome, making the annual habitation and damp check so important. These checks can give an early warning of any damp resulting from faulty or deteriorated body joint sealant, ill fitting or damage to habitation door, windows, seals and locker frames. With typical workshop labour charge between £60-£100 per hour, deconstructing your motorhome's interior to rectify water-damaged areas can run up a bill of thousands of pounds.


CONSTRUCTION
Traditional motorhomes consist of a wooden frame wrapped in a GRP/alloy skin. This is sound but the results are:
• Numerous body joints requiring sealant
• Expensive use of fixing screws, alloy strip and decorative cover beading.
Sealant can harden and screws can rust away the resultant cracks can allow water to penetrate between and behind panels, often out of sight. The trouble is, once it’s visible from the interior wallboards it can be too late to prevent damage.

Newer motorhome construction methods involve;
• Fewer fixings
• More high-tech bonding techniques
• Interlocking panels and joints
• Stronger plastics placing wood.
• GRP/ABS underfloor protection

This allows for longer warranties, but water ingress can still happen so check the small print. A couple of things to look out for in the terms and conditions are:
• Is an annual habitation service required?
• Does it have to be undertaken at a certain date?
• Or by an authorised workshop?
• Is it transferable if buying a used motorhome from a dealer?
If it’s a private sale or auction you should insist on a damp check, service history and full MoT if possible.


HABITATION SERVICE
The habitation service could be considered as the living area of the motorhome’s MoT. It is not legally mandatory, but most warranties require an annual service. It does not include any areas relating to the mechanical side of the base vehicle.
Not all dealers include the damp check in their habitation service, while others do not check the floor, which is high on the list for water entry!
• The actual cost to the customer also varied with prices ranging from £100 by a mobile fitter, to £264 at a manufacturer’s service centre. On average, expect a figure of around £200 including the damp check.
• Make sure you request damp check percentage figures displayed on an illustrated chart and tick list.
• The service should take a minimum of three to four hours.

DAMP CHECK METERS
You can pick one up for £10 online or in a DIY store although motorhome service centres use versions that are much more expensive. Most meters have prongs: Look for previous pinholes and stick the meter in these areas. If you do find damp consult a professional.

AVERAGE METER READINGS
Damp meters give reading indicating the presence of water expressed as a percentage.
• 0-15% are fine
• 15-20% needs attention
• 21-30% indicates remedial action is required
• Over 30% means structural damage and deterioration is occurring
Note that all wood contains moisture, the amount will vary depending on time of year and current weather conditions.

HOW CAN YOU HELP TO AVOID WATER INGRESS?
You can help keep water out from,
• Checking skirting joints
• Don’t use powerwashers or even hoses
• Keep an eye on all windows and door seals
• If there is any spillage clear it all up properly
• There could be holes from DIY add-ons etc: Roof racks, bike stands, TV aerial and any other wires
• Avoid condensation when cooking, use pan lids and open a window
• Mould is a sign of water that hasn’t been dried up properly
• Create air flow at night, or use breathable mesh underlay for bedding
Remember water doesn’t have to be coming from where the leak is. It could be running along pipes or any wires. Condensation is not a fault, so any damage to soft furnishings will not be covered by warranty.

MAIN AREAS TO CHECK
When looking for motorhomes or even maintaining yours keep an eye out for damp, useing a damp meter, eye and nose:
• Underneath for failure of floor seals
• Rear wheelarches: constantly subjected to road grime
• Bouncy floor
• Awning and roof joint trims
• Roof mounted accessones and rooflights
• Door and windows surrounds
• Inside cupboards andunder seats/beds
When looking at second-hand motorhome use the meter, eyes and even your nose, if you smell damp, walk away.

This is an extract from a longer article in the September 2014 MMM magazine. To order your copy, click here

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