How to make a fabric waterproof?
How to make a fabric waterproof?( τεντεσ τιμεσ)
The manufacturers announce the waterproofing index on 2 constituent elements: the outer wall and the floor. This index is generally more important for the floor of the tent than for the flysheet. Impermeability by contact is more difficult to ensure; the tent floor must be even more robust than the flysheet. It must be resistant to splashes, rain, humidity, punctures and abrasion.
To make a fabric waterproof, the process used is coating which consists of coating the surface of the fabric with a coating to make it permeable to water and possibly protect it from UV rays. There are several processes:
Polyurethane (PU) coating. applied in thin layers to the fabric. The thicker the layer, the more waterproof the fabric, but the heavier it is. PU makes it possible to achieve impermeability values from 800 mm to 10,000 mm.
Thermoplastic polyurethane (TPU) coating. This coating offers better wear resistance, better bonding and therefore greater durability than conventional PU coatings.
Silicone coating: generally applied to nylon, silicone is an elastic and durable coating that penetrates the fabric and changes its properties. It increases tear and UV resistance. It is applied in superimposed layers on the 2 sides of the fabric. It increases the lifespan of the colors of the tent.
The more waterproof a tent is, the heavier it will be and the less breathable it will be.
The waterproofing of a synthetic fabric tent is not permanent. The index announced when buying a tent will drop with use. Exposure to the sun (ultraviolet) will destroy the water repellency of the coating and reduce the strength of the fabric. In the long term, your tent will be less waterproof and more sensitive to tears. It will be necessary to regularly apply a waterproofing and UV blockers on the exterior walls in order to limit the phenomenon.
In conclusion and in the field!
To choose your tent , you must determine the conditions of use: location, season, altitude, environment. The waterproofing index is an important selection criterion to take into account.
It is impossible to ask for total waterproofing from a tent.
Depending on the weather conditions: heavy rain, storm, thunderstorm, wind, the water pressure increases on the tent. In the field, you will encounter several normal phenomena:
Condensation inside the flysheet
Impermeability vs condensation
Condensation is a natural phenomenon. The humidity in the ambient air condenses and settles inside the wall. When it rains, the air and the earth are saturated with humidity, which favors the appearance of condensation. It is therefore possible in rainy weather that small water droplets fall inside the tent. This phenomenon can become even more important if there is wind: the water droplets are then vaporized. This is not a problem of impermeability but of condensation because synthetic nylon and polyester fibers do not breathe very effectively unlike cotton.
The passage of several small drops of water is always possible and does not constitute an impermeability defect of the tent.https://tentes-skiasis.gr/tentes-times/