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In Between Joists

When it comes to fitting water underfloor heating pipes between joisted or suspended floors, we have three different solutions that are sure to meet your needs.

As all joist systems do require for the pipes to be spaced around 200mm apart or less, it would be best to select a multiple-space or conservatory-style kit for this type of job. This ensures that you will have enough fixtures to provide the optimum amount of heat coverage.

So, let’s take a look at these three great solutions for piping between joists:

Spreader Plate System

In this solution, screws or nails are used to attach aluminium spreader plates to the joists. These items have been designed with 16mm preformed grooves, which are fixed at 200mm distances to allow for the highly efficient 16mm diameter multi-layered barrier pipes we stock.
As long as the joists have enough depth, a standard installation would involve fixing batons to their sides, around 70mm down from the top of each one. After this, a foiled-faced insulation product, such as Celotex or Kingspan, is carefully shaped and placed onto each baton before the pipes are simply clipped straight into the spreader plates.

In Joist Foil Boards

This system uses unique panels that combine the insulation and spreader plate concepts into one solution. The 50mm XPS insulation board has preformed grooves at 200mm intervals, with the whole panel covered with aluminium foil. This helps the items to dissipate heat evenly across the surface above, meaning that there won’t be any cold spots.
Once again, batons would be fixed to the joists if they are not too shallow, with a gap of around 70mm from the fixtures’ top edges. The boards would then be positioned atop the batons, before the pipes are simply clipped into the fitting grooves.

Dry Biscuit Mix / Screed System

If you are using air source heat pumps and the joists have been structurally approved to be able to take some extra weight, this solution may be right for you. This is because the dried screed mix is able to store a lot of heat for longer than the other joisted solutions, meaning it acts like a big radiator.
When it comes to fitting a screed system, you will again want to make sure the joists have enough depth for the batons to be fixed in the same way as the other solutions, before a foiled-faced, 50mm insulation is trimmed and fitted on top of them. The pipes are then clipped directly onto the insulation, before the dry biscuit mix is poured on top, bringing it up to the joists’ level.
When using this solution, we recommend putting a fine polythene membrane across the top of the dried screed, which stops moisture from building up and affecting flooring.

What Kit is Best For You

Once you have decided what type of floor construction you have and the installation process needed, find out which different heating kit is best suitable for your project.