What is a tule?
A tule is the Dutch term for a small, tubular connecting piece. In construction and building services the word covers several components that have one thing in common: they are short and hollow, and they join two parts or guide a fastener.
Meanings
- Pipework: a short pipe piece or spigot, for example between a flange and a bend.
- Compression fitting: the small ring (olive) around the pipe in a compression fitting is also called a tule in Dutch. Tightening the nut squeezes it onto the pipe to make a tight seal.
- Cables: the sleeve or boot at the end of a cable, such as on a network plug.
- Flat roofs: a telescopic tule is a plastic sleeve that, together with a screw and pressure plate, mechanically fixes insulation and roofing membranes to the deck. In English it is usually called a telescopic sleeve or tube fastener.
The telescopic sleeve on a flat roof
With mechanically fixed roofing, the screw runs through a plastic sleeve. The screw head sits at the bottom of the sleeve, not directly under the membrane. When people walk on the roof and the insulation compresses slightly, the sleeve slides down with it instead of the screw head punching through the membrane. Because the sleeve is plastic, a shorter metal screw is often enough, which reduces the thermal bridge through the insulation. For tapered insulation on concrete there are adjustable systems with a concrete screw that bridge varying insulation thicknesses.
Application
- Fixing insulation and membranes to steel, concrete or timber-based roof decks.
- Bridging thick or tapered insulation (roof falls).
- Connections in water, gas and heating pipework.
Practical tips
- Stick to one system: sleeve, screw and plate are designed to work together. Don’t mix parts from different brands; permitted loads are given in the manufacturer’s documentation or European Technical Assessment (ETA).
- Choose the right length: sleeve and screw length depend on insulation thickness and deck type. With tapered insulation, measure at several points.
- Number of fixings: the number per square metre follows from a wind uplift calculation, with more fixings in corner and edge zones.
Related terms
- Compression fitting
- Flange
- Roof covering
- Roof slope
- Thermal bridge
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