Manufacturers and contractors are welcome to contribute to the Expert Advice section. Schlüter-Systems have prepared a series of advisory technical articles relating to the ongoing problems associated with movement in floor tile installations. Contract Flooring Magazine leads the way for publishing such expert advice online for reference by the flooring, building and construction industry.
Contract Flooring Magazine articles are read by industries top professionals and decision makers including Architects, Specifiers, flooring and building industry manufacturers.
If you would like to contribute to this section, please contact us.
Read our definitive series on movement joints and why they are needed. We also cover the technical aspects regarding their installation.
Schlüter®–Systems 'Ian Knifton' expert in this field, have contributed a Movement Joint Series of technical articles. A valuable trade resource.
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| Article Index |
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| Traditional Fix For Underfloor Heating Problems |
| Hydronic Heating Tubes Revolutionised |
| All Pages |
Underfloor heating systems have no visible heat emitters such as radiators to disfigure walls, and they generate gentle, controllable heat while offering low running costs, special precautions must be taken to counter the effects of thermal expansion and contraction.
The current boom in underfloor heating is bringing its own set of problems for tiling contractors and specifiers: temperature changes within the screed mass of underfloor heating installations -- whether water or electric – lead to the screed moving at a different rate from the tile or stone surface. The rigid surface simply cannot cope with the degree of movement, and the tiles split or debond.
Underfloor systems are increasingly being recognised as an ideal way to warm a variety of rooms, both in domestic applications and commercial buildings. They have no visible heat emitters such as radiators to disfigure walls, and they generate gentle, controllable heat while offering low running costs.
But all too often they are fitted without sufficiently protecting the tiles from movement. Frequently just flexible tile adhesive is used, which doesn’t always provide a total solution against the range of movement caused by underfloor heating. Therefore, special precautions must be taken to counter the effects of thermal expansion and contraction.
Schluter has had numerous enquiries from tilers who’ve been wary of fixing over heated screeds because of problems they’ve experienced in the past, and from contractors called in to undertake remedial work.
If a “traditional” fix is required, where the tiles were originally installed directly onto the substrate, most problems can be overcome by using an uncoupling membrane such as Schluter-DITRA to neutralise the differential movement between the substrate and the surface. It will also bridge and neutralise any cracking in the substrate.
Furthermore, recent tests have proved that the air channels on the underside of the membrane actually aid in the heat distribution, helping the floor to heat up more evenly.
Many installers have also been using uncoupling membranes in conjunction with recent developments in technology which makes the fitting of underfloor heating pipes much easier and far less labour-intensive than traditional methods. Subfloor and screed construction with the use of hydronic heating tubes has been completely revolutionised by a new modular system.
A studded polystyrene panel, known as BEKOTEC, is placed either directly over a load-bearing substrate, or over traditional acoustic/heat insulation. The studs form a grid pattern, with a distance of 75mm between them, to accept heating pipes of a diameter between 10 and 18mm from a variety of underfloor heating manufacturers’ systems.
Stress build-up due to shrinkage, which occurs naturally during the curing of the screed, is successfully eliminated by the formation of micro-fine cracks. As soon as the screed can be walked on, the uncoupling membrane is bonded to it, and the ceramic tile or stone covering is then installed onto the membrane. We’ve been involved with installations where the screed has been laid on Friday and the tiling commenced on the Monday.
With traditional systems, the screed can typically be between 65 and 75mm, or even thicker in some instances, but using Schluter- BEKOTEC means that the height of the overall assembly, including the screed, is only 52mm. Installers say that because of its lighter weight and lower assembly height it is also fitted faster than traditional underlays.
An additional benefit from a design and installation perspective is that surface intermediate movement joints do not need to be cut into the modular screed. This allows greater flexibility with tile design and eliminates the risks associated with cutting movement joints into screeds containing heating pipes.
Also, the screed doesn’t curl. But most importantly, the surface coverings are guaranteed not to crack or debond.
And since the screed mass to be heated is relatively small, the floor heating is easier to regulate, and can be operated at a lower temperature.
Next time we look at how contractors can use the very latest one-system-combination of tile protection technology and underfloor heating to earn more money, by project-managing the entire underfloor heating contract.
For more information contact:
Stewart Bint
T: 01530 813396
F: 01530 813376
