Why is pipe insulation in lofts, a must?

Your home becomes more energy-efficient and cost-effective with insulation. When you jam-pack your facilities with insulation, you help Britain achieve its carbon neutrality goal.

Loft Insulation is often one of the most sought-out ways to insulate your home. When you lay down a minimum of 270mm thick mineral wool insulation on the loft floor, you save almost £150 every year. But are you really doing enough? When you lay loft insulation in between and over the joists, your loft could get quite cold. Won’t the pipes in the area be affected by the cold?

Leaving pipework un-insulated in any corner of your building is asking for trouble. Temperatures may freeze, leading to severe ramifications like pipe bursts or leaks due to which the insulation nearby could also get wet. It is especially true for your cold loft space. 

Our focus here is on pipe and water tank insulation in the vulnerable and neglected area of the home, the loft space. 

Why insulate the pipes in the loft?

The reason: Most British homes have pipes and plumbing in the loft. The space will have a couple of water storage tanks, plus some hot or cold-water distribution pipes. You can also find boilers, central heating pipes and hot water cylinders in the roof voids, in the loft area of some homes. 

One of the side effects of making your home nice and toasty with lots of mineral wool insulation on the loft floor is that the loft space gets quite frigid in the winter. During an extended cold spell, with no heat source available, the loft can become so chilly that the water in the pipes could begin to freeze.

The effect: You may not even realise what is going on above your bedroom until it is too late. As long as the winter lasts and the ice stays frozen, it cannot make things soggy down below. So, the problem may not even be visible until summer kicks in. 

Once the cold spell ends, the ice thaws and the water damages your furniture, walls and the building, in general.

The solution: You can avoid this situation in two ways: 

  1. Skip loft insulation and accept insanely high energy bills. 
  2. Or Lag all the plumbing in the loft area.

Option two is much cheaper and practical.

What type of pipe lagging should i choose?

There are many pipe lagging options available today. You can buy pipe insulation online or visit your local vendor. Some of the most commonly used pipe lagging products include:

  1. Foam Pipe Insulation: Polyethene foam pipe lagging from Armacell, comes in lengths of 2m. It is an easy to install foam pipe insulation, that effectively insulates pipes in lofts, cavity walls and other corners of the building. 
  2. Class O nitrile rubber pipe lagging: Nitrile rubber lagging solution from KFlex insulation is available in 2-metre lengths. It comes in many forms, including unsplit tubes, sheets and a pre-slit self-seal lagging. This versatile pipe insulation finds use in household, plumbing and HVAC applications.
  3. Phenolic Foam Pipe Insulation: Phenolic pipe insulation from Kingspan is one of the thinnest, most thermally efficient solutions available in the market today. This water-resistant pipe lagging can insulate all kinds of pipes in HVAC and building applications. 

Choosing the right foam pipe insulation:

When buying foam lagging for pipes in the loft area or in general, you need to understand what the quoted specifications stand for. Keep these two points in mind:

  1. Diameter of the pipe: The standard pipe diameters are 22mm and 15mm. However, 28mm pipe diameter is not very uncommon.
  2. Insulation thickness: Pipe insulation is available in different thicknesses. As a general rule, thicker insulation is better for hot water pipes as it means less heat loss from pipes. Similarly, thicker insulation on cold water pipes means more protection against freezing temperatures. 

Keep in mind that the quoted pipe diameter is the internal diameter, so a 15mm pipe will be somewhat larger than 15mm when measured from the outside. It is best to choose the larger size if you are uncertain. 

How much pipe lagging do you need?

Ideally, you would always choose thick insulation because there is no harm in excess insulation.Pipe insulation materials are commonly found in 1m or 2m lengths. Measure the entire length of all the pipe runs in your loft before purchase. Buy a bit of extra pipe lagging and do not let the project stall due to insufficient supplies.
It is a bit rare to find solitary pipes in the loft area. Even if you spot one, it is usually attached to a wall or joist. In places where two or more pipes are run close together or butted up against a wall, placing thick insulation can be difficult. If you cannot place 
foam pipe lagging on these pipes, then inserting multiple strips of foil insulation into small spaces can be a feasible alternative. 

A brief walk around your loft may introduce you to pipes such as plastic overflows or gas supply pipes. Plastic water pipes are much more flexible than metal pipes, making them less prone to breaking if water freezes. However, there's no harm in taking precautions and insulating these as well. 

Lagging waste pipes, though, may not be necessary. As they are made of plastic and have a larger bore size, a little expansion from occasional trickles, won't harm them. 

How to insulate pipes yourselves?

Installation of pipe insulation is super easy. You can do the task yourself and save on the installation charges. 

Tools required:

  1. Foam pipe insulation for pipes
  2. Measurement tape
  3. Saw mitre
  4. Duct tape, Foil Tape or cable ties.
  5. Marker pen

Installing foam pipe insulation:

Straight runs:
Wipe the surface of the pipe length that needs insulation with a clean cloth. Measure and note the length of the pipe. Now, using a saw mitre or a sharp knife, cut the pipe lagging to the required size. Open the pre-cut slit in the foam insulation and slip it over the pipe. 

Seal the insulation together using double-sided tape, adhesive or duct tapes.

When using self-seal insulation from K-Flex, simply slip the insulation over the pipe and remove the adhesive strips. Apply little pressure and join the insulation together by pushing the two sides together with your thumb. 

Cut a 90-degree wedge-shaped section on the pipe insulation of the main pipe segment. To make a point, cut the end of the tube that would be joined at 90° at two 45° angles. Now, insert the pointed end into the main tube's 90° cut-out. Wrap the duct tape around the T-piece to seal the junction.

90-Degree bends: For a 90-degree sharp curve, cut the ends of the two lengths at a 45° angle. Attach both to the pipe at the 90° right-angle bend, with their 45° ends meeting. Use duct or foil tape to seal the junction. 

You can find further instructions for insulating pipes on our website or our blog

Water tank insulation in loft:

Many houses have two tanks in the loft area: The bigger tank is used to store and supply water to all the bathtubs, toilets, and sinks in the house. It reserves cold water for all purposes. 

A second, also called header tank, a much smaller one, provides water to the heating system. The smaller tank feeds the heating system and offers an additional area for the water to expand as it heats up.

Both of these tanks contain float valves, similar to those found in toilets, which prevent water from entering when they are full. Lofts are free of tanks, only if your home has a mains-supplied system, such as a combination boiler or a new pressurised unvented cylinder.

Why insulate hot water tanks?

By insulating hot water tanks, you enjoy a warm bath. Hot water tank insulation ensures that the water remains hot so that you won’t have to re-heat it. The insulation reduces energy consumption and costs. 

How to insulate hot water tanks?

Hot water cylinders older than 25 years frequently have a red insulation jacket with parts of the copper body showing. In most homes, you can find a pre-insulated, traditional copper hot water cylinder, with a green-yellow foam finish. 

Insulating a water tank with an extra jacket is a good idea. It is easy to install and effectively insulates hot water tanks. Insulation jackets  for hot water tanks come in many sizes. To know the right size of your water tank, measure the diameter and the height of the tank.  

The insulation jacket can be held in place by a string looped around the cylinder's top and 'belts'. Follow the maker's instructions while fixing the jacket around the tank. 

Why insulate cold water tanks?

Coldwater storage tanks in lofts are often found without a lid and exposed. They can freeze in the winter, just like pipes. While you make an effort to insulate pipes, why not spend a few quid more to avoid wasting almost 230 litres of water? 

There is another advantage to insulating cold water tanks. In summer, water in tanks can reach 30°C, which serves as a perfect temperature for bacterial growth. While most of them may be innocuous, we are sure you don't prefer drinking or bathing in bacteria-infested water. 

Your cold-water tank is probably 50+ years if it is made of galvanised steel, asbestos or cement. Instead of spending money on insulating it, our suggestion would be to replace it with a newer model. The majority of tanks found in households today are made of black plastic.

How to insulate cold water tanks?

First off, close the water tank with a lid before you insulate it. Check the label on the tank or measure its length, height and width before purchasing insulation online or from your local vendor. The sides of any water tank in the loft should be insulated. 

Water tanks can be insulated using 50mm insulation boards. You can find pre-cut packs to fit around conventional water tank sizes. They can be further trimmed to fit individual tanks.

Insulation jackets are also available in standard or bespoke sizes to fit around all types of tanks. Carefully measure the tank to know the right jacket size you need. Also, check the position of any overflow feeding into the tank. Loosely secure the sides of the jacket to the tank with string or foil tape. 

Ensure that the insulation jacket is so arranged, that you get easy access to the ballcock.

In conclusion:

Water tank and pipe insulation saves them from freezing, reduces energy costs and increases the service life of your plumbing system. By insulating the pipes and water tanks in the loft area, you will not only ensure that your home is energy-efficient but also that the insulation laid in your loft remains dry. Just a few quid more, and you will have ensured energy saving in every way possible. 

For everything, you need to insulate lofts, pipes and water tanks, visit Buy Insulation Online . We deliver top-quality insulation products for free in major cities and plant a tree for free on every order. If you are ever unsure of the right size of pipe insulation or valve jacket for you, you can request a call-back, and our experts will be happy to clarify your doubts.


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