Good tents and rain flies are designed with as few seams as possible to avoid leaking. However, since virtually any seam can allow water to enter, each and every critical seam must be sealed. Most new tents arrive with either factory taped seams or regular unsealed seams. You'll be able to recognize factory sealed seams by a material tape glued to the seams. If your seams are taped you don't need to apply a seam sealer. On the other hand, if your tent seams are of the untaped variety, you'll need to apply an after-market seam sealer. There are several seam sealers on the market, but the product is not as important as proper application.

If you decide to use seam sealer, you'll need to apply two coats to both sides of the seams, waiting until the sealer dries between each coat. If you apply sealer on only one side, apply it to the coated side of the material. Pay close attention to getting the sealer into the needle holes. After applying the seam sealer, don't use the tent or stuff it away for a day or so to let the sealer bind properly. If you've applied the seam sealer carefully your tent should be sealed for the season.

Unfortunately, most of the seam sealers I've tried quickly peel and delaminate, requiring periodic reapplications. There is, however, an alternative to the annual seam sealing ritual. It's a product known as Seam Grip and is rapidly becoming the sealer of choice. My experience with Seam Grip is that while application is not a fun experience, it has to be applied only once, works very well and appears to last. It's very slow drying, but when it dries, it forms a tough, thick, soft and flexible permanent bond to the seam. At about six dollars for a 1 oz. tube, Seam Grip is probably the most expensive seam sealer on the market, but don't settle for less. It's extremely durable and is good to take along on trips to make emergency repairs. Seam Grip can be purchased from your local outfitter as well as ordered from most of the outdoor catalog suppliers. It's the best sealer I know of and is what I've used for years.

Application of Seam Grip is a tedious but simple job. First, set up the tent, put the rain fly on upside down and stretch it out for an hour; then stretch it tight again. This allows the seams to stretch and the stitching to open as much as possible. Before applying the Seam Grip, wipe the seam with Seam Grip Pre-Cleaner or 90% Isopropyl Alcohol to be sure it's clean. Then, while pulling the seam apart to expose it to the Seam Grip, run a small bead of the sealer down the seam and work it in with the brush. Be sure to thoroughly coat the seam, but don't use more Seam Grip than you need. Keep in mind, Seam Grip is virtually permanent and if you accidentally let another part of the tent get into the sealer before it sets up, it may stay there forever. Take your time, and if you have to stop, rinse the brush thoroughly with Isopropyl Alcohol. Heating the tube of Seam Grip in hot water for about fifteen minutes will allow it to flow easier. Seam Grip generally takes twelve to twenty four hours to fully cure, but by using the optional Seam Grip Cure Accelerator you can reduce the curing time to about two hours.

Be sure to seal around the tent floor section, but sealing the seams above the waterproof bathtub floor section isn't necessary. Don't overlook areas like the cordura reinforcement that may be at the base of a pole. Sometimes it's not enough to seal just the stitching since water can run down between the cordura and the tent material and seep through that way. You may need to cover the edges, the stitching, and in some cases, the entire section of cordura.

After the Seam Grip has fully cured, and before you stuff it back in its stuff sack, lightly dust all of the fresh sealer with baby powder or talcum powder. Even though the Seam Grip has dried, it will still adhere permanently to itself.

Speaking of stuffing, the best method for carrying your freshly sealed tent on a trip is by stuffing it into its stuff sack. For long term storage at home, the tent should be loosely stuffed in a large, breathable sack. I don't recommend folding a tent since this can lead to accelerated wear at the creases.

Simply sealing the seams is no guarantee that your tent will stay dry. You should always use a ground cloth, since it takes only one small stone to make your seam sealing worthless. It's very important that your ground cloth be totally under the tent. If part of it is allowed to hang out beyond the floor of the tent it will act as a rain catcher and funnel water under the tent. Also make sure the rainfly is not touching the tent body or moisture will eventually be wicked through the interior walls of the tent.

With a little effort and preparation, you can ensure your tent stays dry no matter what the weather.