Canvas sag after heavy rain

Submitted: Saturday, Dec 30, 2017 at 17:07
ThreadID: 136035 Views:7680 Replies:8 FollowUps:7
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Hi all

Woke this morning to the maiden voyage of our new Black Series Alpha being marred by heavily sagging canvas in one of the annex rooms after a long nights rain. I followed all the instruction guides and videos and am unsure why the rain didn’t just flow down but instead elected to find a couple of nice squares between poles to pool. I’m concerned the canvas roof may have stretched and lost its waterproofing ability. Time will tell I guess, but does canvas stretch? And would it contract? One unsupported 2.4m stretcher bar has bent slightly, everything else seems fine though, no structural damage, no poles came down. Probably a good 30L was sitting in one particular crevice though.

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Reply By: IvanTheTerrible - Saturday, Dec 30, 2017 at 17:52

Saturday, Dec 30, 2017 at 17:52
Canvas needs to be well wetted before use to expand the fibres so they seal out water when it rains
AnswerID: 615791

Follow Up By: EpicBP - Saturday, Dec 30, 2017 at 19:04

Saturday, Dec 30, 2017 at 19:04
Thanks. I’ve seasoned it. I’m just wondering if the sagging may have stretched (and compromised) the canvas material on its first real use in the rain? Is that even possible?
FollowupID: 886863

Reply By: Dean K3 - Saturday, Dec 30, 2017 at 19:16

Saturday, Dec 30, 2017 at 19:16
Rain hasn't done it any real harm in that sense as ivan says its really does need to have several good drenching for it to swell up properly and become water tight.

If possible carry a extra pole with suitable attachments to add extra support to area where water collects. Ideally a swing up short pole in middle of span will help prevent collection. I spotted this feature on a ostrich swing out awning on a unit imported from south africa, and these guys know there quality n build.

same climatic conditions as ours but also have better product than say Asian sourced units
AnswerID: 615792

Reply By: Alloy c/t - Saturday, Dec 30, 2017 at 19:32

Saturday, Dec 30, 2017 at 19:32
Should be no lasting damage as such , just remember to always have the roof canvas 'tight' and that there is always ' slope ' away from collection points.
AnswerID: 615793

Reply By: Gronk - Saturday, Dec 30, 2017 at 21:06

Saturday, Dec 30, 2017 at 21:06
Canvas...tents.....camper trailers.....and rain ??

Always the compromise between size and space between poles or supports ! And fall !!

I've had 2 KK's and with the big awning up, it was always a struggle to get the water running off the roof instead of lying on it.
Anything will sag with weight on it....the idea is to get the water to run off before it can pool. Trial and error..
AnswerID: 615800

Follow Up By: rocco2010 - Saturday, Dec 30, 2017 at 22:17

Saturday, Dec 30, 2017 at 22:17
Trial and error all right.

I swag it under an ARB awning and got caught out in the rain last month. Set it up with a slope but the slope wasn't enough to stop water pooling.

there will be a steeper slope next time.

But at least the water pooled and didn't seep through on to me!

FollowupID: 886872

Follow Up By: Frank P (NSW) - Saturday, Dec 30, 2017 at 22:41

Saturday, Dec 30, 2017 at 22:41
Ditto for me a few weeks ago, rocco.

Makes me wonder about the usefulness of the 4 side walls you can get for a car awning that turn it into a tent. Fine in the dry, but I think useless in rain - you'd end up wet and with a broken awning.

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FollowupID: 886874

Follow Up By: rocco2010 - Saturday, Dec 30, 2017 at 22:57

Saturday, Dec 30, 2017 at 22:57
You're probably right Frank.

If I was likely to be caught in proper rain I think a proper tent would be the go.

FollowupID: 886876

Follow Up By: Dean K3 - Sunday, Dec 31, 2017 at 10:51

Sunday, Dec 31, 2017 at 10:51
Rocco I've had both experiences a cheaper tourer had its own internal water feature, after about 10mm of rain. nothing beats quality

I also had a issue with arb tourer awning water collected within middle of canvas and acted as a collector, how the velco didn't rip apart is beyond me. I ened up carefully collecting it in container (dish-washing tub) chucking it into the water tanks at the campsite I was staying.

This is where I was pleasantly surprised to see a swig up pole on the south african ostrich awning pops canvas up enough to prevent collection points - a simple but very effective method.
FollowupID: 886901

Reply By: gbc - Sunday, Dec 31, 2017 at 08:09

Sunday, Dec 31, 2017 at 08:09
There’s a good chance your guy ropes have eased a bit being your maiden voyage too. When preparing for rain we drop the sides and ends a bit to get good fall off the roof. Looking pretty is for when the sun is out. The canvas won’t have stretched unless it has held a large amount of water.
AnswerID: 615808

Follow Up By: EpicBP - Sunday, Dec 31, 2017 at 22:07

Sunday, Dec 31, 2017 at 22:07
Thanks gbc. The canvas had probably sagged about 15cm (6in) below where it was when I went to bed. It was easily 20-30L of water which is a fair bit of weight when you think about the span being about 1.5m-2m square. Took me getting the little ladder with the plastic top step and putting some muscle under it to lift it up to empty it off. Hard to know if the canvas has stretched or if the sag was due to guy ropes/poles all giving a bit. Doesn’t look too bad now, but I’m not convinced it’s all as tight as it originally was so when I’m back home after this trip I’ll be opening it up and setting up from scratch again to make sure it is all taut. Hopefully a bit more water and sun will reverse any potential damage done to it. All the seams and zips in the area looks fine so if it has stretched, it will be minimal I hope.
FollowupID: 886935

Follow Up By: gbc - Sunday, Dec 31, 2017 at 23:09

Sunday, Dec 31, 2017 at 23:09
I’ve woken to fairly large puddles in the annexe before. The canvas has survived. I trust yours will.
FollowupID: 886937

Reply By: rumpig - Sunday, Dec 31, 2017 at 09:52

Sunday, Dec 31, 2017 at 09:52
With the extra bedroom on the back of our camper there is no real option to slope the roof more then it already does, it does however have an eyelet in the middle that I tie a rope on and go to a peg in the ground, then pull that section down lower forming a V of sorts in the roof for water to run down and not pool....might be an option for you?
AnswerID: 615815

Reply By: wbsl - Sunday, Dec 31, 2017 at 11:34

Sunday, Dec 31, 2017 at 11:34
I have owned 4 different make and model camper trailers, all pooled water in the awning if it wasn't supported. To solve the problem I used spreader poles to help support the canvas and give it less sagging for water to pool in.
The spreader poles were supported between tent poles near the side of the side of the camper to and the outer awning tent poles. The additional spreaders with C clip end in between to support the weight of the wet canvas. Usually used 2 per span.
Only fitted them up if I thought it was needed, but did end up carrying significantly more poles to do the job. Once these were in place I had no issue with pooling water on any of the campers.
Regards Wayne
AnswerID: 615830

Reply By: Von Helga - Thursday, Jan 11, 2018 at 09:51

Thursday, Jan 11, 2018 at 09:51
When your canvas is set up do you happen to have a horizontal spreader bar that the rain water has to flow over?
It only take a small amount of water to be unable to get over that bar for the pool of water to be created, once it starts then most of the rest of the rainwater stays on the roof.
If you have horizontal bars, then look at the slope of that part of the tent and look to increase the angle of the canvas in that area so as water does not start to collect at all in that position. ie lower your vertical poles a little more
Some annexes would actually work better ( from a water run off point of view) if there were not spreader bars along the lower edge of the annex roof.
AnswerID: 616019

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