The ultimate guide to Horse rugs

The Ultimate Guide to Horse Rugs

We all love buying rugs. We all have a growing collection and can never quite bring ourselves to throw away the one with 50 rips and no buckles left, because one day we might need it, and if we are honest, we are a little attached to it. But do we really know what we are buying, how rugs work, and how to care for them properly?

This guide covers everything: what denier means, how waterproofing works, which rug weight to use and when, how to wash and store your rugs, and how to tell if your rug still fits. If you need to know how to measure your horse, head to our step-by-step rug measuring guide. To browse the full range, visit the Masta hub or shop all horse rugs at Harry Hall.

What is denier in horse rugs?

Denier refers to the strength and durability of the outer fabric of a rug, not its waterproofing. The higher the denier, the tougher the outer shell. A higher denier rug will resist tears and abrasion better than a lower denier rug, which matters if your horse is hard on his rugs, rolls frequently, or lives in a herd where rugs get grabbed and pulled.

As a general guide:

  • 600D — suitable for quieter horses with good turnout conditions
  • 1200D — better for horses who are tough on their rugs, or exposed to rough ground, fencing, or herd turnout

It is a common misconception that a higher denier means a more waterproof rug. This is not the case. Waterproofing is determined by the membrane coating, not the outer fabric weight. All Masta turnout rugs, whether 600D or 1200D, use the same waterproof and breathable technology, hydrostatic head tested to 5,000mm.

Waterproofing explained

A waterproof membrane is bonded to the inside of the outer fabric. This membrane stops water passing through the fibres while still allowing air to circulate. The effectiveness of this membrane is measured using a Hydrostatic Head test.

In a Hydrostatic Head test, the fabric is stretched flat under a sealed tube of water one inch in diameter. The test is observed over 24 hours to measure how many millimetres of water the fabric can withstand before moisture penetrates. The result is expressed in millimetres. The higher the number, the better the waterproofing.

HH Rating Protection Level Suitable For
1,500mm British Standard minimum Light, short showers only
3,000mm Good standard protection Moderate rainfall, average conditions
5,000mm High performance (all Masta rugs) Prolonged rain, wind-driven weather, heavy storms

Masta rugs are tested to 5,000mm, the equivalent of withstanding five metres of sustained rainfall. Seams are also sealed with specialist tape to prevent water penetrating at stitch points, which is one of the most common weak points in cheaper rugs.

Over time and with general wear, waterproofing will gradually degrade. The outer DWR (Durable Water Repellent) finish can be restored with a specialist reproofing product designed for horse rugs. For a deeper explanation of how waterproofing and breathability work together, read our guide to understanding horse rug waterproofing, breathability and weather performance.

Why breathability matters

A rug that keeps water out but traps heat and moisture underneath is not doing its job. Breathability is just as important as waterproofing, particularly for horses in work, native breeds who run warmer, or horses turned out in changeable British weather where temperature swings are common.

The waterproof membrane in a breathable rug contains microscopic pores that are smaller than a water droplet but large enough to allow water vapour to escape. This means sweat and body heat can pass out through the rug, keeping your horse comfortable rather than clammy.

If you find your horse feels damp underneath their turnout rug, this does not necessarily mean the rug has leaked. In heavy sustained rain, the outer pores of the membrane become temporarily covered by water, reducing breathability and allowing condensation to build up inside. This is particularly common in summer when temperatures are higher and humidity increases. The rug has not failed. It is working as designed under extreme conditions.

To check whether your horse is comfortable under their rug, place your hand at the base of the neck or just behind the front legs. They should feel warm but dry. Hot and damp indicates over-rugging; cold indicates under-rugging. For more on reading the signs, see our guide to avoiding over-rugging your horse.

Which rug weight do I need?

Rug fill weight is measured in grams and determines how much warmth a rug provides. Think of it like the tog rating on a duvet. The right weight depends on temperature, whether your horse is clipped, and whether they are stabled or turned out.

As a general guide:

  • 0g (no fill) — waterproof protection only, no added warmth. Suitable for dry, mild weather or as a base layer
  • 100g (lightweight) — light warmth for cool autumn days and changeable spring weather
  • 200g (mediumweight) — a versatile mid-layer for most UK winter conditions
  • 300g (heavyweight) — for cold spells, clipped horses, or horses who feel the cold
  • 400g (extra heavyweight) — severe cold weather or horses who are fully clipped and stabled

Use the temperature guide below as a starting point, then adjust based on your horse's individual needs:

Situation -10 to 0°C 0 to 5°C 5 to 10°C 10 to 15°C 15°C+
Stabled / Clipped 400g 300g 200g 100g No rug
Stabled / Unclipped 300g 200g 100g 0g No rug
Turned Out / Clipped 300g to 400g 200g to 300g 100g to 200g 0g to 100g No rug
Turned Out / Unclipped 200g to 300g 100g to 200g 0g to 100g 0g No rug

These are starting points, not rigid rules. A healthy, unclipped horse with good body condition is generally comfortable down to around 0°C without a rug. Over-rugging is a more common problem than under-rugging in the UK. If in doubt, go lighter and check regularly rather than adding more weight. For a full temperature and rugging guide developed by the Masta product team, read our post on how to avoid over-rugging your horse.

Types of horse rug

Turnout rugs are designed for horses living out or spending time in the field. They have a waterproof and breathable outer shell, a fill for warmth (or no fill for summer use), and are built to withstand movement, rolling, and the elements. This is where denier matters most. Browse the full Masta turnout rug range for options across all weights and neck styles.

Stable rugs are designed for indoor use. They provide warmth but are not waterproof and should never be worn in the field. They can be layered under a turnout rug for additional warmth in very cold weather.

Fleece and cooler rugs are designed to wick moisture away from a wet or sweaty coat after exercise. The wicking fabric draws moisture outward while retaining body heat, helping the horse cool down gradually without catching a chill. Not to be confused with stable rugs. They serve a different purpose.

Fly rugs and summer sheets protect the coat from UV, insects, and dust during warmer months. They are not waterproof and should not be left on in rain.

Therapy rugs such as the ProtechMasta range use far-infrared technology to gently increase circulation, support muscle recovery, and help regulate temperature. Particularly beneficial for older horses, those in hard work, or horses managing stiffness and joint issues. They can be used as a stable rug or as part of a warm-up and cool-down routine.

Under-rugs and liners add warmth beneath an existing turnout rug without buying multiple fixed-weight rugs. A 100g or 200g liner used beneath a standard turnout can give you the flexibility of several rug weights from one outer shell, a practical approach for unpredictable British winters.

Not sure which type is right for your horse? Browse the full horse rug range at Harry Hall or visit the Masta hub to explore the complete collection.

How to wash horse rugs

Washing is one of the biggest factors in premature waterproof failure, and the most common mistakes are washing too frequently, at too high a temperature, or with the wrong products.

Before reaching for the hose, assess whether washing is actually necessary. If you can brush off dried mud and wipe down the lining with a warm, soapy cloth, that is often the better option. Every wash degrades the waterproof treatment a little further, so the fewer washes, the longer the rug performs.

If the rug does need a proper wash:

  • Hand wash at a cool temperature using a non-biological soap or a specialist rug wash product
  • Never use biological detergents or standard laundry powder. These break down the DWR waterproof finish
  • Step away from the pressure washer. High-pressure water destroys the membrane and will leave you with a rug that no longer performs
  • Never tumble dry. Always dry naturally, away from direct heat and direct sunlight
  • Reshape the rug whilst damp to ensure any fill lies flat before it dries fully

Once completely dry, a specialist reproofing spray or wash-in proofer designed for horse rugs can help restore the DWR finish. Reproofing once a season is good practice. It will not restore a damaged membrane, but it will extend the life of a rug that is still structurally sound.

If your rug needs a deeper clean, professional rug cleaning services use specialist equipment that cleans effectively while minimising damage to the waterproof treatment. Worth considering for heavyweight winter rugs at the end of the season. For more detail on how waterproofing degrades and how to maintain it, read our guide to horse rug waterproofing and weather performance.

How to store horse rugs

Summer is the right time to give winter rugs the attention they need before putting them away. A rug stored in poor condition will not perform well when you need it most.

  • Always store rugs completely dry. Damp rugs stored away will develop mould, and mould degrades the membrane over time. Metal buckles and fittings will also rust
  • Use resealable storage bags where possible. Many Masta rugs come with them. They keep rugs clean, dry, and compact in the tack room
  • Store in a cool, dry place away from direct sunlight. UV exposure over long periods affects the lining and outer fabric
  • Before storing, check for damage. Small tears, broken buckles, and worn leg straps are all much easier to address now than on the first cold morning of autumn
  • Keep spare buckles and leg straps from old rugs before you dispose of them. They are useful to have on hand and often interchangeable

Ready to find the right rug?

Now you know what to look for, browse the full Masta range, built for British weather, tested to 5,000mm, and trusted by horse owners across the UK for fifty years.