Understanding denier, thread count and tent specifications and coatings

Tents specifications and coatings can be confusing. What is Denier, Thread count and Hydrostatic Head? Understanding tent specifications and terms will help you choose the best tent for your needs.

When looking at tents for sale reputable brands and retailers should provide tent fabric specs so you can work out a tent’s performance capabilities and suitability to handle different conditions. Here's an introduction to different tent fabric specifications. For more on fabrics check out fabric pros and cons


What is Denier?

Denier (D) is the unit measuring the weight and thickness of the individual threads used in the fabric. Fabric with a higher Denier will be thicker, stronger and more durable than the same fabric with a lower Denier – 40D Nylon will be stronger than 15D Nylon and 150D Polyester stronger than 75D Polyester. Remember that different fabrics have different strengths. Lower Denier is common in ultralight nylon tents and tarps where low weight is paramount. Polyester camping tents typically have higher 68D, 75D, 150D fabrics, while for camping and event shelters something around 150D would be recommended to deal with the greater stresses and longer exposure to the sun and elements.


What is Thread count?

The thread count (T) is the number of threads used horizontally and vertically per square inch of fabric ... 210T means a total of 210 threads. A higher thread count represents a greater density and tighter weave in the fabric. For this reason you will often find lower Denier fabrics (with a ‘thinner’ thread) have a higher thread count.


What is Ripstop?

Ripstop tent fabrics are those with a special reinforcement to increase resistance to tearing and ripping. When weaving, a stronger thread is used at regular intervals to form a crosshatching, grid pattern visible in the fabric. This improves strength of the fabric and makes any tears or holes less likely to spread and become bigger.


What is gsm?

GSM (grams per square meter), refers to the weight in grams of one square meter of raw woven canvas or polycotton canvas. (Also still measured in ounces per square yard as well.) A higher gsm means a higher fabric weight and thickness. Most tents range from around 280gsm to 380gsm with more modern polycotton canvas closer to the lower end.


What are fabric coatings?

Chemical coatings are applied to tent fabrics to increase their performance, especially resistance to water. 


What is a silicone coating? What is silnylon?

A silicone coating is usually applied to nylon, hence silnylon. The coating ‘permeates’ the nylon fabric creating a stronger silicon ‘reinforced’, waterproof nylon fabric with better stretch and tear strength. Silicone repels water and so it’s easy to shake off excess water and dries quickly. On the down side silicone coatings are more expensive, stop ‘breathing’ in the fabric which may lead to greater condensation, and result in a very slick and slippery surface meaning that tent seams cannot be taped - Silnylon seams require manual application of a liquid seam sealant. And note that brand logos cannot be printed onto silicone coatings. 


What is a Polyurethane (PU) coating?

Polyurethane or PU coatings applied to polyester and nylon fabrics are more like a layer that sticks to the surface of the tent fabric. It creates a waterproof barrier, is more affordable, has greater breathability than silicone and has a surface which allows the application of tape on tent seams. But it doesn’t reinforce a fabric’s strength in the same way as silicone, requires some care to be kept clean and dry for storage, and will affected by UV exposure and break down over time. Branding can be printed directly onto PU coatings.


What is a SIL/PU coating?

Some tent fabrics have a silicone coating on the outer side and PU coating on the inner side as a compromise, balancing the benefits of both coatings and allowing tape to be applied to seams making tents ‘ready to go’ for end users. Branding will be printed on the underside of the fabric but not on the outer side.


Hydrostatic Head (HH), water column or ‘waterproof’ ratings (measured in mm)

Polyester and nylon fabrics are not waterproof and so silicone or PU coatings are applied to give waterproof properties. The amount of water that they can ‘hold out’ is tested using a high column of water which is measured in mm. Ratings range from 800mm up to a max of 10,000mm with ratings of 1500mm and higher generally considered ‘waterproof’. See our article on how to choose a waterproof tent for a better explanation of waterproof tents and ratings. DCF (Cuben fiber) is waterproof and canvas has a natural waterproof performance so these typically do not have mm ratings.


What other fabric coatings are there?

A number of other coatings can be applied to tent fabrics to improve UV resistance, water resistance (allowing water to bead and roll off), rot and mildew resistance and to add fire retardant properties to fabrics.


What is Oxford?

Oxford is a different type of weave which provides better strength and durability than standard plain weaves. Often used for heavier duty fabrics.


What to look for in your next tent fabric specs?

Generally, the higher the denier count the stronger and heavier the fabric will be, and the higher the mm rating the more ‘waterproof’ it will be. Have a look at the following ...

  1. 75D 185T Polyester PU1000mm – a standard polyester tent fabric suitable for camping tents but has a lower waterproof rating of 1000mm suitable for light rain only so probably more suitable for casual camping in fairly good conditions.
  2. 20D 330T Ripstop Nylon Sil/PU 3000mm – a light 20 Denier nylon fabric suitable for ultralight tents, ripstop so has better tear resistance, silicone coating topside and polyurethane coating underside so can have taped seams, good waterproof rating at 3000mm should be able to deal with most rain.
  3. 380gsm Polycotton Ripstop – a heavier, durable modified polyester and canvas blend suitable for swags, and family cabin tents reinforced with Ripstop ‘grid’ threads, it's canvas so has natural waterproof properties
  4. 150D Oxford Polyester PU 3000mm UV – a heavier, thicker polyester with a stronger weave, more suitable to event shelters and tent floors, waterproof with 3000mm HH rating and coated for greater resistance to UV.


As well as identifying your preferred tent design, you’ll need a tent fabric with the right balance of strength, durability, waterproofness, weight and budget to meet your needs. Knowing more about tent specifications will help you get the right tent. At Intents Outdoors we put careful consideration into these factors to create tents fit for purpose with the right combination of specs and features at affordable price points.

Tents nz

Leave a comment

All comments are moderated before being published