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WE HAVE JUST BOUGHT A KHYAM CLASSIC XL TENT IT STATES CERTAIN SEAMS NEED SEALING BUT DOES NOT SAY WHICH ONES. DOES ANYONE KNOW WHICH ONES?

HAS ANYONE ELSE GOT THIS TENT AND WHAT DO THEY THINK OF IT?

Hi there - first of all, posting in capital letters makes it look like you are shouting....

I think Khyam, and a lot of other makes, say this as a general proviso and include a tube of seam sealant as standard. The only way to be absolutely certain about it is to put the tent up and test it either in the rain or with a hosepipe to see if there is any leakage on the seams. If there is, then the seam sealant can be used to treat those areas.

I did a long post about how to do that so I will go to see if I can put a link here.

Nope - can't find the thread I posted ,but because it was long and complex I saved a copy of the text, so here it is in case you need it.

Waterproofing, condensation and leaks in man-made fabric tents.

Manmade fabrics get their waterproofness from the inside layer of PU that is chemically bonded to them. The rating is measured in HH (=Hydrostatic Head)  and is the height of a column of water (given in mm)  that can sit on the patch in tests, before the water comes through the fabric. Hence, a rating of 3000HH means that a 3 m column of water could sit on the fabric before it leaked. However, it is wise to bear in mind that there are lots of other factors that can lead to water getting into your tent, including the direction that the wind is driving the rain, as well as factors described below (condensation and leaks).

Condensation

Manmade fabrics are not breathable, unlike cotton canvas, so there is a build up of condensation inside the tent. This comes from our breath, from cooking, boiling the kettle, burning gas etc and can be considerable, leading to something akin to indoor rain and puddles! So ventilation of your tent is vital, whatever the weather outside. Condensation can sometimes be mistaken for leaks, so before concluding that you tent is leaking, you need to work out the source of the water. This is best done by using an old towel or similar, to wipe up all the condensation and mop up the water you have found; then you need to watch that gathering point in order to work out if it is coming through a seam or is just a collection of condensation. Once you have detected a leak, then it is simple to treat, following the steps below.

Causes of Leaks

When stitched, manmade fabric does not recover to fill the stitch holes like cotton canvas does. Therefore most manmade fabric tents have a heat bonded clear tape placed over all the seams in order to seal the stitching. This is why most of these tents will be advertised as having taped seams.

Also, the chemical bonding of the PU layer is prone to breakdown caused by UV light, therefore most tents only have a life time of about 20 weeks exposure. Hence, the lifetime of your tents depends on how often you camp. Once that PU bonding starts to go, the PU coating comes away on the inside; this often first appears as patches of whitish plastic, where the PU is no longer just a clear coating on the fabric because is has pulled away. Once this starts to happen, no amount of exterior treatment with waterproofing agents will replace the functions of the degraded PU layer. Waterproofing sprays only help to make exterior water bead up and run off, rather than collecting on the fabric outside, so they are of limited value. So, once the PU layer has reached this level of degradation, it is probably time for a new tent.

However, if you have deduced that  your problem is a leak in a seam, then the following steps are advised for treating it.

Sealing a leaking seam

1) Detect the source of the leak!  Typically, this will be at a point on the seal where either the tape has not sealed down properly, or there are several layers of stitching, because it is an anchor point for loops or ties of some kind, such as a lamp hanging or bedroom hanging point.  Make a detailed note of the location of the leak, so that you can find it again when the tent is dry.

2) The tent must by dry when you apply the sealant.  Seam sealant is readily available from camping shops, and usually comes in either a tube with a little brush or a squeezy bottle with a sponge applicator on top.  Personally, I prefer using a brush because it is possible to really work the sealant into the stitching and layers. Apply a thin layer of the sealant to the area that needs treating. Make sure all the layers of fabric have been treated, and that your working area is ventilated as you do so, because the sealant gives off volatile fumes.

3) If you need to treat any ties or loops too (which may be acting as a wick to draw water in from outside) then weight these with a peg or similar whilst they dry, so that they hang downward away from the tent and don't stick to the flysheet. 

4) This is sticky stuff that needs a full 24 hours to dry, so keep the tent up whilst it dries. As a final precaution, you can also dust the treated area with talc before you put the tent away, so that any residual stickiness is mopped up, thus preventing the tent from sticking to itself when folded.

there's more

it's about wicking.

the links are old and the pictures are no longer there but Andy's advice is worth reading.

nb: i haven't had a problem since i have had the annexe as it is effectively an extra fly sheet over the tab points.

Libethy

If you have got the tent up to seal the seams do all of them, then you know they are sealed.

Les D