What is a counter-lattice and what are its functions? Is it needed and how to install it? Let's take a look at all the technical points together, and finally, I will show you step by step how to properly mount a roofing pie with a counter-lattice.
The place of the counter-lattice in the roofing pie
Before deciding whether a counter-lattice is needed, let's first understand:
- what it is;
- how this node differs from the rest of the details of the roofing;
- what it is for.
The difference between the crate and the counter-lattice
According to the rules, a crate is the base on which we mount the finishing roofing material (metal tiles, slate, corrugated board, etc.), and the main function of the counter-crate is to provide ventilation in the under-roof space.
As can be seen in the diagram above: a waterproofing material is laid on the rafter legs, which holds the counter-rail, and the bars of the main crate are already stuffed on top of it.
The main crate itself is of two types:
- Solid crate, that is, stuffed with a single carpet, here it is used as an ordinary planed or tongue-and-groove board, as well as sheets of plywood or OSB. As a rule, solid flooring is mounted under a soft roof;
- Discharged crate, this is when the boards are attached with a certain step. This design is more common, and most importantly practical, because it is much better ventilated. A sparse crate is mounted under metal, slate, profiled sheet, ceramic tiles, in general, under almost all hard materials.
Why you need a ventilated roof
We figured out the terms, now let's talk about what the counter-lattice is for, is it possible to “throw away” this element altogether and immediately fill the batten boards onto the rafters? The fact is that condensate (dew point) always falls on the border of warm and cold air, and this border runs along the finishing roof.
If we lay a hydrobarrier on the rafters and directly fill it with a roofing transverse lathing, then the condensate will have nowhere to go, and it will begin to actively soak into the wood.As a result, no matter what you impregnate the tree, it will last no more than a year, then it will begin to rot.
In addition, basalt wool is usually used for a warm roof, and any wool loses its properties when moisture enters. Sooner or later, the moisture locked under the roof will seep down and soak into the cotton mats, and then you can forget about the insulation, since wet cotton wool is useless, plus it does not recover when it dries, it needs to be changed.
We conclude: by raising the main crate a little, we provide good ventilation of the roof space and guarantee the safety of the truss system.
The counter-lattice can be neglected in only one case - if you do not plan to make a warm attic. For example, in the summer kitchen or in unheated outbuildings. But if you later change your mind, then the roof will need to be completely re-covered, just insulating from below will be very problematic.
The subtleties of mounting a roofing pie with a counter-lattice
Installation of the counter-lattice does not require any fundamental knowledge, the instructions below are available to any master who knows how to work with a hammer and a hacksaw, the main thing is not to confuse the sequence and observe the dimensions.
Arrangement of the roof plane
The technology depends on the angle of inclination of the slopes, the steeper the roof, the more difficult it is to sheathe it, we will talk about the installation of a roofing pie with a large slope.
| Illustrations | Recommendations |
 | Tool:
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 | Material. Counter batten or counter batten - Most truss systems are assembled from 50 mm thick timber, and the counter batten is often taken with the same width.
On roofs with a small quadrature, you can take a rail 30-40 mm high, and for large roofs I always take a bar 50x50 mm. |
 | The optimal width for a board under a crate is 10 cm, while the thickness should be at least 25 mm.
The step of the sparse crate depends on the configuration of the roofing material, for example, for ordinary slate it is 20-30 cm, and under the metal tile you need to look at the size of the wave (this information is in the instructions). |
 | Wood protection.
Before installation, all wood, including the counter rail, must be treated with a complex antiseptic. |
 | We fix the seal.
In order to prevent condensate from leaking out, and to keep the waterproofing tightly, we attach foamed polyethylene to the counter bars on one side:
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 | Installing stops. On steep roofs, along the perimeter of the box between the rafters, a thrust bar is attached to the screws, it is needed to hold the insulation. The height of the stop is equal to the width of the rafter leg, in this case the rafter is 50x150 mm, respectively, we set the stop 25x150 mm. |
 | We fasten the tape.
To fix the membrane of the hydrobarrier, we glue butyl rubber tape “K-2” and double-sided tape along the edge of the dropper. |
 | Hydrobarrier.
For the roof, I try to take the Strotex V hydrobarrier, the price per roll ranges from 800–1000 rubles.(prices for spring 2017), the quality suits me. |
 | We fix the counter-lattice.
The roof grille is not attached immediately:
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 | We fill the crate. When one tape of the canvas is rolled out and secured with counter-beams, I begin to stuff the roofing sheathing. Planks 100x25 mm I fill from top to bottom. First, the planks are fastened with self-tapping screws, and then 120 mm nails are additionally hammered. |
 | note:
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 | At the junction, I drive 2 self-tapping screws 100x5 mm into each plank, then I go through another 120 mm nails.
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Arrangement of the ridge and valley
Competent installation of valleys and skates is no less important than the arrangement of the roof plane itself. I will talk about the main points separately.
| Illustrations | Recommendations |
 | Ridge arrangement. The counter-lattice device is a kind of pipe. From below, cold air enters through the air vents and rises up through the gap between the counter rails. So that the air at the top can escape, the ridge cannot be closed tightly, air vents are also made there, and so that the insulation does not “pull” moisture from the air, it is covered with a hydrobarrier membrane. |
 | On a roof made of soft tiles with a continuous crate, ridge ventilation is mounted using metal structures with a mesh. |
 | If the ridge is sewn up tightly, then several ventilation, roofing air vents are mounted nearby (no further than half a meter) in increments of 2.5–3 m. |
 | Arrangement of the valley.
A valley is an internal junction of two adjacent roof planes. On the adjacent sides of the valley, valley boards are stuffed, the minimum size of this flanging is 150 mm. |
 | We lay the membrane.
The waterproofing membrane in the valley is laid in 3 layers. The first 2 layers are overlaps of the canvas from adjacent planes, and the third layer is rolled out a roll of waterproofing, from top to bottom throughout the valley. |
 | We fill the crate of the valley.
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Conclusion
As you can see, the roof counter-lattice is mounted quite simply, but it cannot be neglected. In the video in this article, you will find recommendations for arranging a roofing pie for different coatings. If you have any questions, welcome to the comments, I will try to help.
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