If it is a polyester tent it shouldn't leak at all through the material but may through the seams...even from new.
What you may get during heavy rain is condensation being knocked off the roof of the tent by the force of the rain making a spray inside and giving the impression the tent is leaking. Heavy condensation can also bead and drip off the roof or run down the walls of the tent, especially in the corners giving the impression the seams are leaking.
As I understand it polyester is not waterproof in itself but is laminated on the inside with polyurethane which waterproofs it to a certain standard but allows it to 'breath'. The outside of the material is then sprayed with silicon or a similar water repelling agent which causes water to bead and run off the tent aiding the waterproofing abilities.
After many months of use or abuse the outer silicon can wear off and water will soak into the outer fabric causing damp patches to appear but should not penetrate right through unless the inner polyurethane layer has also been damaged.
At this stage you can 'reproof' with something like Fabsil which will allow the water to bead and run off again making the tent more aesthetically pleasing and since it also contains a UV protection it will help preserve the material a little longer.
Once the material itself has started to break down all the spraying in the world won't help much and the tent will need replacing. The material at this stage becomes less pliable and starts to show signs of cracking. You will often get signs of this quite early on the entrance to the pole sleeves where they are regularly abused. It is not a problem on the sleeves. I have never managed to wear a tent out yet.
There is no reason at all why you should need to keep reproofing a polyester tent once you start but the outer layer will continue to wear off with use so you may wish to spray it if it shows further signs of water soaking in.
I believe that if you spray a canvas tent it may have a detrimental affect in preventing the fibres from swelling when wet and creating natural waterproofing, so you may then have to keep spraying it once you start.
Quote: Originally posted by Bob61 on 20/8/2016
As I understand it polyester is not waterproof in itself but is laminated on the inside with polyurethane which waterproofs it to a certain standard but allows it to 'breath'. Post last edited on 20/08/2016 11:43:58
Sorry to disagree but, polyester tent fabric doesn't have breathable qualities, that's why they suffer so much from condensation and why it's so important to use the vents etc.
I'd suggest pitching the tent and getting a hose pipe on it, just to see if it really is leaking (I do agree with Bob61 about it potentially being condensation) then have a look where it's coming from. If there is actually dripping through the seams then do as suggested and apply some seam sealant (apply inside, when it's all bone dry again).
A tent that's been used for just 8 weeks and correctly stored shouldn't need re-proofing. IMHO, when a synthetic tent is ready for re-proofing it's when it's about ready for the bin.
Quote: Originally posted by Bob61 on 20/8/2016
As I understand it polyester is not waterproof in itself but is laminated on the inside with polyurethane which waterproofs it to a certain standard but allows it to 'breath'. Post last edited on 20/08/2016 11:43:58
Sorry to disagree but, polyester tent fabric doesn't have breathable qualities, that's why they suffer so much from condensation and why it's so important to use the vents etc.
I beg to differ...if it wasn't breathable you would never get the air out when trying to roll it up and stuff it in it's bag. You would end up with a big balloon.
Also, the quality of the waterproofing is determined by the hydrostatic head. If the volume of the water on a polyester tent exceeds it's HH the material will allow water through (the tent will leak). It couldn't do that if there weren't any 'oles in it
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Topic: When to re-proof tent?
