Advice Please on Canvass Sides

[JMPC]

Hi All,

I built an off-road camper trailer last year, for pics see earlier thread I posted on this forum...

http://www.expeditionportal.com/forum/showthread.php?t=35494


I am now building another one, with some improvements.

However, I am currently stuck on a major decision, which is what to make the walls and roof out of.

I could make them as before, aluminium for exterior, polystyrene insulation and PVC or GRP for inside walls.

However, I have recently thought about making the exterior walls out of a marine grade canvass like Sunbrella, or Topgun. These are the type of waterproof yet breathable canvases that you´ll find on the back of leisure boats. I live near a marina, so have quizzed lots of boat owners who live aboard to ask whether or not the canvasses are truly weather proof in all conditions and everyone has said 'yes, completely water proof, never had any problems at all. I live in the UK so winters are long with lots of rain.

I have spoken to couple of firms who can make me a complete canvass set up, complete with integral windows, fly screens, blinds. The canvass would then be dropped over a steel frame and secured down at the bottom of the walls with lockable clips.

Advantages of this are...

Very light, approx. 60kg for all the roof, walls and windows.

Windows will open up completely ( like the front of a tent) so giving a great 'outdoors feeling' on warm days and nights even when inside. And I can have the windows any size I want.

Manufacture is obviously much easier because I am just dropping a complete canvass over a metal frame, and the whole unit is ready.

I could still line the interior walls with GRP or PVC, and probably still have insulation between the exterior canvass and the interior walls. Or I could just go rough and ready and not bother with any kind of lining, just go for a tent style feel inside.

Between the metal frame and the exterior canvass I would place a lightweight mesh cover, (think chicken wire) effectively making it impossible for anyone to break in.

What are peoples thoughts on this?

Would you still be worried about the windows being a week area, and prone to people breaking in?

What dis-advantages do you percieve?

Any thoughts most welcome

All the best
JMPC

 

[ntsqd]

If the "tent" can move against the frame at all it will abrade any coating and the metal itself. Probably won't do the metal much harm, but it won't do the coating any good. Bare metal exposed to condensation held in place by the "tent" (~capillary action) would be the result.

Solve that and I think it's a novel solution. Not sure that if I were going to go to the trouble of building a trailer that I wouldn't want hard sides, but it's not mine.

 

[Tucson T4R]

On my KK trailer I have enough canvas to set up an entire MASH unit. :sombrero:

My experience has been that good canvas is fully weather proof but the down side is when it gets windy. As long as you have a solid frame to mount the canvas to it will stand up to the winds but it can get pretty noisy inside with high winds and all the canvas banging around.

If winds are not a big problem where you live it may be a great design for you. If you get abused frequently with high winds then I would go for a hard sided design.

 

[JMPC]

If the "tent" can move against the frame at all it will abrade any coating and the metal itself. Probably won't do the metal much harm, but it won't do the coating any good. Bare metal exposed to condensation held in place by the "tent" (~capillary action) would be the result.

Solve that and I think it's a novel solution. Not sure that if I were going to go to the trouble of building a trailer that I wouldn't want hard sides, but it's not mine.

Yup, good point, the capillary action is a possible problem. I have spoken about this with the canvass manufacture who assures me it won't happen becasue of the type of coating on the canvass on its exterior. Not quite sure how this works but the evidence is there in that the boat canvases dont suffer form this.

Thanks for the feedback

 

[JMPC]

On my KK trailer I have enough canvas to set up an entire MASH unit. :sombrero:

My experience has been that good canvas is fully weather proof but the down side is when it gets windy. As long as you have a solid frame to mount the canvas to it will stand up to the winds but it can get pretty noisy inside with high winds and all the canvas banging around.

If winds are not a big problem where you live it may be a great design for you. If you get abused frequently with high winds then I would go for a hard sided design.

Thanks Brad,

good to hear your experiance concerning 'weatherproofness' bears out my research and what I am being told, so that certainly reassures me.

It is a good point you make about the wind noise, (romantic for about 5 minutes and then nothing but stressfull) I intend to have lots of points where the canvass will attached firmly to the metal frame, approx. every 50cm in every direction, so that should keep things tight. It is also another point in favour of lining it with interior walls and insulation just to offer a barrier against unwanted noise.

Thanks
JMPC

 

[ntsqd]

Does the material also have that coating on the inside surface? I'm not thinking that it could wick moisture in from the outside, but rather that the moisture exhaled from breathing inside the trailer could condense on the surface and drain towards where the canvas is pulled tight against the frame.

 

[JMPC]

Does the material also have that coating on the inside surface? I'm not thinking that it could wick moisture in from the outside, but rather that the moisture exhaled from breathing inside the trailer could condense on the surface and drain towards where the canvas is pulled tight against the frame.

I´m not sure if coating is on both sides? I guess though if condensation is going to be a problem it will happen with or without the coating?

I am concerned about condensation, wich is one of the reasons I may line the interior with walls. If not, I´ll make sure that there is plently of cross venitaltion high up in the roof to try and eliminate the worst of it.

 

[etbadger]

The pop-top sides on our van are a plasticized canvas of some sort. We do get a significant amount of condensation in colder temperatures and humid climates. Some of this is alleviated by using chemical air-dryers (calcium choloride crystals) used for damp closets and camper storage (or snow melt).

Additionally we have all our heat and cooking done with sealed diesel appliances which vent outside.

-e

 

[Lynn]

You mentioned the inside mesh to provide security. Someone passing by with a knife might be tempted to cut the canvas to see what they could grab. Yes, the mesh will then stop them, but the canvas is still cut.

Hard walls should deter most of the less-determined criminals, not to mention the random opportunistic idiot with a pocket knife.

Just a thought.

 

[JMPC]

You mentioned the inside mesh to provide security. Someone passing by with a knife might be tempted to cut the canvas to see what they could grab. Yes, the mesh will then stop them, but the canvas is still cut.

Hard walls should deter most of the less-determined criminals, not to mention the random opportunistic idiot with a pocket knife.

Just a thought.

Yes, you are quite right and this is my biggest concern too. As you say, it is perhaps inviting breakin attempts or just mindless vandalism. A way of detering breakins could be to advertise on the side that there is protective metal mesh'. Not sure exactly how this could be done effectivly, but sure there is a way.

Don´t know if vandalism could be guarded against? This is tricky

Thanks for your reply, ultimatly, given a choice, which would you prefer, the benefits of canvass (lighter weight and able to create a much more open environment when camping) or hard walls?

All the best
JMPC

 

[JMPC]

The pop-top sides on our van are a plasticized canvas of some sort. We do get a significant amount of condensation in colder temperatures and humid climates. Some of this is alleviated by using chemical air-dryers (calcium choloride crystals) used for damp closets and camper storage (or snow melt).

Additionally we have all our heat and cooking done with sealed diesel appliances which vent outside.

-e

I am guessing these are bags of crystals that you place strategically aroung the inside?

Are you using a 'webasto' diesel applicance?

I suppose even though the combustion takes place outside, cooking itself, like boiling water, must create lots of condensation. Here what do people do, leave windows and doors open, or rely on extracter fans?

 

[compactcamping]

Personally I'm a big fan of the "softsided" approach as a way to notably reduce weight and potentially have a smaller in transit profile.

The challenge is waterproof and breathable. There are a number of fabrics that do a good job of balancing the two. A double wall design does help in dealing with condensation.

Here is a frame I've been playing with for a fabric wall camper.

 

[JMPC]

Personally I'm a big fan of the "softsided" approach as a way to notably reduce weight and potentially have a smaller in transit profile.

The challenge is waterproof and breathable. There are a number of fabrics that do a good job of balancing the two. A double wall design does help in dealing with condensation.

Here is a frame I've been playing with for a fabric wall camper.

Hi, thanks for the photo, and feedback. Yes double walled design might be a must to avoide the worst of the condensation.

I am aware of 3 big brands for the canvass, Sunbrella, Topgun and Harbourtime. Are you ware of any others?
Great to see someonelse sees the merit in this idea. Are you intending to have windows? Waht are you going to use for the interior wall, something solid, or another breathable lightwight fabric that wicks away the mousture, like the inside of a tent?

All the best
JMPC

 

[compactcamping]

There are lots of fabrics to choose from. I find it most cost effective to figure out the criteria it needs to meet and see what is readily available from my local supplier. My fabric source carrys Tri Vantage and Glen Raven fabrics. Topgun and Harbor-Time are both Tri Vantage products, Sunbrella is from Glen Raven.

Sunforger and Weather-Mate are cotton marine canvas I like. HydroKing is a poly/cotton blend canvas that looks promising.

I'm still very early in sorting out this idea. Yes windows, thinking exterior flaps than can act as awnings. Interior wall a lightweight cotton canvas, very breathable and moisture wicking. Exterior wall, waterproof coated fabric, with some form of an overlaping panel design that allows for adjustable ventilation between the walls.

 

[JMPC]

There are lots of fabrics to choose from. I find it most cost effective to figure out the criteria it needs to meet and see what is readily available from my local supplier. My fabric source carrys Tri Vantage and Glen Raven fabrics. Topgun and Harbor-Time are both Tri Vantage products, Sunbrella is from Glen Raven.

Sunforger and Weather-Mate are cotton marine canvas I like. HydroKing is a poly/cotton blend canvas that looks promising.

I'm still very early in sorting out this idea. Yes windows, thinking exterior flaps than can act as awnings. Interior wall a lightweight cotton canvas, very breathable and moisture wicking. Exterior wall, waterproof coated fabric, with some form of an overlaping panel design that allows for adjustable ventilation between the walls.

Thanks Scott,

Interesting stuff. Like the idea of exterior flaps working as awnings, that hadn´t occured to me, but great idea.

All the best
JMPC