Van roof waterproof

Tips for waterproofing your van in short form:

  • Try and do it under cover, if not, not in the heat of summer
  • Take the time to figure out exactly how much sealer to apply before squeezing down your extrusion, because its hard to clean up.
  • Consider the windows and door too

The first down pour reviled a drip coming from the center hatch in the caravan’s roof. I know the tricky thing about leaks is that they don’t always start where they end. The water can travel internally for a long time before turning up in your house. Add to that my fear of being stuck in a small leaky box while the world out side is getting drenched, being forced to watch the particle board that makes up my furniture, dissolve like weet-bix. I looked up on the roof of the van and it told a history of someone madly sikaflexing, gutter sealing and wet-edging up the whole roof in between downpours. The interior roof looks fine, so their messy system worked.

I couldn’t bring myself to add another layer of goop to the patchwork, so I said “Right. I’m resealing the whole van. Then I’ll paint a waterproof membrane over the whole lot and sleep with a smile through the rain.

Long story short: after a month of stripping, sealing and painting (in the peak of summer with 47 degree Celsius days), I discovered a crack in the skylight, the source of the drip.

On the plus side, my van is sealed up tighter than a fishes a-hole and has an extra insulated roof! Here’s how I did it.

This is what it looked like to start with. There is one aluminium extrusion on each side of the van that runs from the front bottom corner, up the front edge across the roof and down the back edge.

I scraped all the layers of sealer off with a paint scraper. Then unscrewed and lifted the rails and wire-brushed the soft sealer back to bare metal.

Someone had gone nuts with this weird beige stuff that didn’t seem to be mixed properly and had a lot of bubbles. The wire brush just melted and spread it, so I just did my best to get rid of the bubbles.

The cracked vent needed to be replaced, it was cracked at every screw hole and missing a handle. The new one is aluminium.

There were a lot of opinions about what to seal a caravan with. The camps seem to be: something that will never come off, or something that can come off when it inevitably has to come off (they remain soft in the center – mastics).

There is a product called caravan sealer which I found out later is 50% cheaper than Butyl-Mastic – what I used. I unloaded at least 6 tubes.

Don’t go to fucking Bunnings if you can help it. When they say “lowest prices are just the beginning” what they mean is that they will have low prices until there aren’t any more other hardware stores around. Then they jack the prices up and lay off half the staff.

My idea was to paint the van sealer from one raised edge of the aluminum to the other. There is a rubber strip that covers the screws – purely cosmetic- I was surprised to be able to select my 40yo caravan model from a drop-down box and have it arrive at my doorstep for about $2 per meter.

Theoretically I shouldn’t have had to put the membrane on top after resealing, but I like the idea of redundancy… and insulation, let me tell you about insulation:
On those hot days if you touched the metal roof vents from inside, you would have burned your hand off. After the white rubber paint, they were merely warm to touch- a huge difference that you could feel inside the van. Highly recommended.



Un-dumb Wicking beds

That’s a bit harsh. There is a fundamental difference to the following design though, that I haven’t seen documented on the whole of the internet, so here it is.

A wicking bed is a large scale self-watering pot. There is a reservoir of water you can access underneath, and as the soil drys out, the water is wicked up from the below,  prolonging the time between required watering and the inevitable death of your plants.

When there is a rain event, the bed harvests it’s own water which it will then make use of over a long period of time.

The soil is not going to dry out as long as there is some water in the reservoir.

The water is being delivered efficiently to the roots of the plant, where it is needed. It is being insulated by the soil… and er… mulch (pretend there is mulch on top of the soil in that diagram).

You aren’t as dependent on irrigation, which is less efficient, and easy to brake.

The fundamental difference

Traditionally, people have used a layer of gravel and drainage pipes to hold the soil above the water. The downside to this is that the gravel displaces the water. It’s a technique for building drainage into beds. Alternatively you can use something that takes up less space- that’s all. The water will last longer. You don’t need to get gravel, move gravel, etc.

Credit to Lachie from Tree Frog Permaculture for this pearl of wisdom (that man has whole a van full of pearls!).

No gravel technique

Bath tubs are good, long lasting, water proof vessels which are easy to come by. I can pick up light weight steel tubs for $20 (or less for several) at the local tip shop. They are often pre-plumbed for drainage too.

I build a frame out of recycled hardwood, which is also easy to come by at the moment the timber for this bed was picked up from a building site for free on the way to the job, advertised on Gumtree (Craig’s list, whatever). I won’t go into details about how I built the frame as carpentry is not my expertise. But simply: hold the tub up to a comfortable working height and give yourself room for the plumbing (or dig out a trench).

10cm pvc drain pipe is used to support the weld mesh. Pvc pipe is also easy to come by as a recycled building product and I haven’t had to buy any yet. It is strong and doesn’t displace much water. The weld mesh is cut and bent up to fit the contours of the tub and stop the soil from entering the water.

Geo-fabric is used to line the weld mesh. The edges are tucked under the weld mesh like a bed sheet, so that the fabric is touching the bottom of the bath – in contact with the water even when there is only a little. some extra pieces are draped over in the middle to help with even moistening of the fabric.

Fill the bed with water up to 2cm below the mesh and cut the riser pipe to the level of the water. This will stop the bed from becoming water logged. You will always  be able to gauge the level of water in the reservoir by looking down this pipe.

That’s it. Fill your bed with some good soil… keep enriching it with some nice home made compost (you are turning your food scraps into compost, right?)… and don’t forget to mulch it!

Here’s another design using the same principle. In this case, builders plastic forms the water proof seal and a plastic pallet is supporting the soil.