how to lay underlay

You’ve invested in underlay to make the most of your fabulous new flooring. We would recommend you use a professional flooring fitter to lay both your underlay and new flooring. However, if you’d like to lay it yourself, we’ve put together a guide in order to help including hints and tips from our experts.

what to expect from this expert guide

Before getting stuck into your new home renovation project, it’s important to have everything you need. This easy-to-follow guide will take you through each step on laying underlay in your home, which includes:

Which? approved Carpetright fitters

Which? approved fitters Which? approved fitters

We’re proud to offer a professional fitting service that is approved and trusted by industry experts. Our recommended fitters have all passed the rigorous assessment process set by Which? to become a recognised Which? Trusted Trader.

By choosing to have your new vinyl fitted professionally by our recommended fitters, you’ll be able to enjoy your new floor without the hassle. Select fitting at the checkout or ask one of our friendly advisors if purchasing in store. Alongside our standard fitting service, we offer an uplift and disposal service which for a small fee means the fitters will take up and dispose of your old flooring before they fit your new one.

It’s just one less thing for you to worry about.

Find out what you can expect from our professional fitting service by clicking here.

how to measure a room accurately

As with all DIY jobs, preparation is everything when it comes to flooring and it’s of the utmost importance that you get the room measurements correct.

  • Draw a simple diagram of the rooms that you wish to fit underlay in - these drawings don’t need to be perfect as long as the measurements are accurate.
  • For square or rectangular rooms, simply multiply the width by the height. For example, a room that is 5m x 2m will need 10m² of underlay.
  • Ensure you add an extra 50-100mm to each edge.
  • If your room includes recesses or chimney breasts, you still need to measure the complete surface area without these as the underlay will be cut around them. If this is not easy to work out, measure each individual area and write the measurement in the relevant space on the diagram. Then these areas can be added together to get the total area of the room.
  • Always measure twice to make doubly sure your measurements are correct.
  • Remember to measure to the back of any door frames or room trims.
  • To work out the coverage for steps, measure the height and depth of each step which will give you the length before multiplying by the width. This will give you the area of each step.

How to measure a simple room accurately

Watch our step-by-step guide to accurately measuring a simple room. It's never been easier to get a perfect fit.

How to measure a room with extra areas

Learn the basic steps to accurately measure a room with extra areas by watching our helpful video.

How to measure a room which requires a join

Accurately measure a room which requires a join by learning how from our step-by-step guide.

types of underlay

Carpet Underlay Carpet Underlay

Carpet Underlay

Carpet underlay makes your carpet feel even softer and more luxurious. Underlay absorbs any wear and tear so it doesn’t show on the surface, giving it longevity and maintaining its appearance for a longer time.

Laminate Underlay Laminate Underlay

Laminate Underlay

Laminate underlay serves to add extra comfort to your laminate flooring as well as reducing the flexing that can occur without it when it’s walked on. It also helps to reduce footstep noise on the hard surface, and traps in heat to make your home warmer as it’s a great insulator.

Wood Flooring Underlay Wood Flooring Underlay

Wood Flooring Underlay

Just like underlay for laminate, wood flooring underlay can keep your engineered wood flooring looking stunning for longer and reduce your energy bills by trapping in heat. It doesn’t just keep your home warm, it also cuts down on noise from footsteps and protects your flooring from the damage caused by moisture.

Underfloor Heating Underlay Underfloor Heating Underlay

Underfloor Heating

If you have underfloor heating, you will need to use a specific underfloor heating underlay with it. These specialist products allow air to circulate and their low tog rating lets heat penetrate through the floor.

preparing the floor for carpet underlay

Sweep the floor to clear debris Sweep the floor to clear debris

Firstly, before anything is fitted, ensure the floor is clean and free from nails or staples that could be present if it has previously been carpeted. Give the floor and sweep or vacuum to get rid of any dust and grit or anything lying on the surface that could cause bumps.

Tools you might need include:

  • Utility knife
  • Underlay tape
  • Staple gun
  • Hammer
  • Spray adhesive

fitting underlay for carpet

Fitting underlay for carpet Fitting underlay for carpet

It’s important to use a high quality underlay as this will give your carpet a much longer life. It’s a good idea to also use floor lining paper as this stops the underlay from sticking and protects your carpet from dirt and dust.

  • Roll out the lining paper if you are using it and fix with a hammer tacker or heavy staple gun. Fix around the edges by spraying with adhesive ensuring the rows overlap slightly.
  • Take the underlay and lay it loosely rubber side down. Use the knife to trim it so it is level with the gripper rods.
  • Butt rows of underlay together but do not overlap them. Use carpet tape to join them.
  • If you have doorways and recesses, cut the underlay into and around these spaces. It’s OK but not ideal, to add an extra piece if you need to but make sure it remains flat.
  • Ensuring you keep the underlay straight and gap-free, staple it along its edges inside the gripper. Use adhesive if you are laying carpet onto a concrete floor.
  • Use tape to stick along the full length of joins. Use the knife to trim off any excess underlay inside the grippers.

fitting underlay for laminate flooring

Fitting underlay for laminate flooring Fitting underlay for laminate flooring

There are various types of underlay for laminate flooring each with different advantages. Thicker options offer more sound proofing, which could be a consideration if you are laying a floor in an upstairs room or flat.

  • Bear in mind that not all underlay types are suitable for wet areas such as kitchens and bathrooms while some types come with a built-in damp-proof membrane.
  • Lay the underlay over the entire floor and trim to fit, cutting a 16mm gap around any pipes.
  • Lay lengths parallel and stick together along the length of the joins with masking tape.

fitting underlay for wood flooring

Fitting underlay for wood flooring Fitting underlay for wood flooring

Again, bear in mind that not all underlays are suitable for wet areas such as kitchens and bathrooms but there are some types that come with a built-in damp-proof membrane.

  • Place the underlay at one end of the room and unroll from the wall.
  • Lay lengths parallel using scissors or a knife to trim and stick together with masking tape.
  • Continue in this way across the room. Although we need the edges to meet, it’s important to ensure they don't overlap as this will create an uneven floor.
  • Leave a gap of 10mm around pipes.