Roof Drip, Its Structure And Purpose, As Well As Calculation And Installation Features

2024 Author: Bailey Albertson | [email protected]. Last modified: 2023-12-17 12:53

Roof drip tip: additional element for special purposes

The roof of the house consists of two blocks - a rafter system that performs a load-bearing function, as well as a roofing pie and forming elements, the role of which is to protect the structure from destruction due to the effects of negative atmospheric phenomena. One of these additional elements is the drip, which no modern roof can do without. To install this element yourself, you need to know its structure and installation rules.

Content

• 1 What is a dropper and its purpose

  • 1.1 Video: what is the eaves strip for?
  • 1.2 Video: installation of a drip for skylights

• 2 Roof drip device

  • 2.1 Video: turning the drip at an angle
  • 2.2 Eaves strip and drip
• 3 Standard product dimensions

• 4 Calculation of additional elements

  4.1 Table: the cost of 1 running meter of a dropper corresponding to the width of the workpiece

• 5 Installation of roof drip

  • 5.1 Video: the correct design of the cornice node

  • 5.2 How to make a do-it-yourself roof drip

    • 5.2.1 Video: bending of eaves on a listogib
    • 5.2.2 Video: How to Bend Sheet Metal at Home
  • 5.3 Blitz Tips
  • 5.4 Video: cornice knot - why mount two cornice strips
• 6 Reviews

What is a drip and its purpose

A drip tip is a corner strip, in most cases made of galvanized steel, which is attached to the edge of the eaves over its entire length. The role of the drip is to remove moisture beyond the perimeter of the cornice, ensuring its discharge into the gutters, so that the structural elements of the house and the roof remain dry.

The metal dropper is located in the eaves unit and removes moisture outside the eaves

If you do not mount the drip bar under the waterproofing material, then the condensate accumulated in the under-roof space will begin to fall on the walls, and along them to the foundation and basement, drain onto the frontal board or penetrate into the rafter system, rendering them unusable.

Video: what is the eaves strip for?

Installing a drip helps not only from condensation, but also from atmospheric rains, during which not all water flows from the roof. Some part of it, reaching the edge of the roof deck, smoothly flows to its inner side. And already from there, in the absence of a protective strip, as if along a knurled path, it rushes into the roofing pie, contributing to the wetting and destruction of all its layers. The consequences of this, alas, are very sad - rotting of the crate and rafters, wetting of the insulation, mold, fungus. We can assume that there is no roof.

Therefore, as already mentioned above, no building, no matter what form its facade or roof may be, can do without these protective elements of special purpose, the functions of which are as follows:

• they prevent melt and rainwater from touching the elements of the roof structure;
• are an auxiliary barrier to the invasion of cold air from outside into the house;
• in winter, they protect the rafter system from ice penetration;
• make the roof of the house complete and aesthetically attractive if matched together with other additional elements to contrast or match the roofing.

The dripper ensures the removal of moisture from the roof and under-roof space into the drain

Drippers equip not only to protect the roof. They are also used to drain moisture from window and doorways, balconies and porches.

Drippers are used not only on roofs, but also to drain water from balconies and porches

Video: installation of a drip for skylights

Roof drip device

Roof drippers are divided, depending on the place of their installation, into:

1. Pediment - extensions mounted along the edge of the pediment overhang. Their purpose is to divert water from the gable of the building to the cornice and prevent moisture from entering the rafter system during oblique rain. Frontal drip-tips have 3 folds that divide the drip bar into a skirt, a step and an apron.

   

   Pediment drips are installed on the pediment overhangs to protect the facade of the building from getting wet

2. Cornice - droppers installed along the edge of the cornice overhang and having, in contrast to the pediment drainage elements, 2 bends. The first one divides the drip bar into an apron, which is fixed to the cornice, and a skirt, which directs moisture into the gutters. And the second one serves as an additional stiffening rib on the drip skirt, which gives the structural unit greater strength.

   

   Eaves drip drip condensate out of the under-roof space, providing dryness to all structural elements of the roof

3. Reverse drip aprons - additional components used on pitched roofs or in certain areas of complex structures, where the water flow is directed in one direction. For example, towards the valley. Return droppers are attached to the frontal board and perform the same functions as the usual ones - they protect the ridgeless roof assembly from getting wet and drain water to the roofing, and from there into the drain.

   

   The back drip apron made of cold-rolled galvanized steel with a polymer coating is installed mainly on pitched roofs

In addition, there are parapet drippers designed to protect parapet nodes, drip tides, which are installed in the attic eaves overhang, basement, facade, etc.

The parapet drip is designed to protect the parapet nodes from moisture penetration

Droppers are made on special equipment - listogib, with which it is easy to make protective water-directing connections on your own. This is especially rational when erecting a standing seam roof, when the paintings are done right on the construction site. In this case, scraps of roofing material are obtained, from which, in order to save money, it is advisable to produce various additional elements.

A mechanical listogib machine is used to bend metal plates in the manufacture of panels for standing seam roofing and roofing additional elements

An interesting alternative to metal products for soft roofs are decorative molded aprons, drip lines. They are a roll material with an outer layer of galvanized steel polymer coating. It is a pleasure to work with such add-ons: smear the working area with a special mastic and simply unfold a roll drip over it.

For soft roofs, additional elements in the form of roll material can be used

Video: turning the drip at an angle

The correct roof design with a drip is as follows:

• covering material;
• cornice strip;
• lathing and initial lathing - continuous flooring with minimum gaps of 3-4 boards in the area of the eaves, the width of which varies according to the roofing and is regulated by regulatory documents - SP 17.13330.2016. Roofs, SP 31-101-97, TTK, SNiP II-26-76 * and others;
• counter-lattice;
• waterproofing layer;
• drip;
• rafters;
• frontal strip of eaves;

• gutter brackets and gutters.

  

  The correct construction of a metal roof with a drip must provide good ventilation of the roof space

With such a device, even if there is a large snow cover in the area of the cornice unit, a good flow of air into the under-roof space is provided, which is important for natural ventilation of the roof.

Cornice plank and drip

Often these two additional elements are reduced to one concept - water drainage from the roof and only one of them is installed. This is a big mistake when designing a roof. They are both guiding and waterproofing components, of course. However, the cornice strip does not drain condensate, since it is attached under the covering layer, due to which its main function is to direct the water flow into the gutters.

A ventilation mesh is laid between the drip and the eaves

The drip is mounted under the waterproofing layer, under which the insulation is located, due to which it removes the condensate drops that have penetrated into it and contributes to the dryness of the thermal insulation layer. In addition, as an auxiliary element, it helps the eaves to channel moisture into the drain. In addition, the drip is placed with such a bend that maintains a good air gap, which means that it guarantees the dryness of the roof space.

Standard product dimensions

Metallized droppers have a standard length of 1–2 m, a thickness of 0.4–0.5 mm and a width of 20 cm. You can, of course, make custom-made droppers in all parameters - length, width, configuration, sweep and materials. But the cost of such additions will be more expensive, since the complexity of the order and individuality are taken into account - you will need to configure or reprogram the equipment.

When choosing the length of the product, it must be borne in mind that the droppers are mounted with an overlap of 50 mm, and when choosing the width, be guided by the size of the cornice strip, which should ensure strong attachment to the crate and go into the groove by at least ⅓

Typical drippers are made, as a rule, of galvanized steel, coated on both sides with zinc-alumina or zinc, and in case of individual production from a material at the discretion of the customer - copper, titanium-zinc, aluminum, steel and zinc.

When installing a copper roof or copper drain, additional elements are often used, also made of copper.

In a section, the structure of the feedstock for ordinary droppers is shown in the photo below:

1. Steel sheet.
2. Zinc coating with a density of 275 g / m².
3. Anti-corrosion layer applied over the zinc layer.
4. A primer with good adhesion to metal.
5. Polymer coating of the outer layer - plastisol, polyurethane, polyester, etc.

6. Protective lacquer on the inside.

   

   The structure of metal plates for the manufacture of roofing accessories consists of several layers

Calculation of additional elements

To purchase additional elements, a simple calculation is made - an overlap margin is added to the length of the roof along the perimeter. And when calculating the cost, the resulting value is multiplied by the cost of 1 running meter, which depends on the width of the product, and the cost of fasteners (nails) is added. Some values for an illustrative example are given in the table.

Table: the cost of 1 running meter of a dropper corresponding to the width of the workpiece

Workpiece metal width, mm	Average cost of a running meter of a factory-made drip, rubles
50	70,00
100	95.00
150	110,00
200	126,00
250	140,00
300	155,00
350	170,00
400	185,00
450	200.00
500	215,00

Consider an example: droppers will be mounted along the entire length of the house, equal to 60 m. The length of one product is standard 2 m, the width of the workpiece is, say, 30 cm, and the fixing step is 100 mm.

1. We determine the required number of extensions: 60: 2 = 30 pieces + overlap (30 x 0.05 = 1.5 m, i.e. 2 products). A total of 32 extras or 64 running meters.
2. We calculate the cost using the data in the table: 64 x 155.00 = 9920.00 + the cost of 600 nails (with a step of 0.1 m) weighing 1 gram each = 9920.00 + 54.00 = 9974.00 ≈ 10000, 00 rubles.

As can be seen from the example, on the scale of the entire construction, this amount is negligible. However, having spent it and installing droppers, you do not need to worry about the safety of all structural elements of the house in the future.

Roof drip installation

Before starting work, you must prepare:

• all additional elements;
• hammer and scissors for cutting metal;
• galvanized nails 3-5 cm long.

If necessary, replace the nails with self-tapping screws, and then replace the hammer with a screwdriver. The installation process is carried out before laying the roofing and is carried out in the following order:

1. Remove the protective film and fix the dropper to the eaves board, which is recessed in the plane of the rafters. The width of the eaves must be sufficient for the subsequent fastening of the drainage system.

   

   The dripper is attached to the frontal board, recessed in the plane of the rafters

2. Individual elements are overlapped. For a better connection of the drip planks, the stiffening rib of each part is cut by approximately 2 cm and this end is brought under the previous plank.
3. To fix the waterproofing film, a special double-sided self-adhesive sealing tape is glued on top of the dropper in its upper part. On the rafters, again, a waterproofing film is laid on top of the drip, if it has not been previously laid, and fixed with a stapler to the base. The film is laid with a sagging of 1–2 cm.
4. Remove the protective film from the sealing tape and fix the waterproofing to the drip, smoothing out pinches and creases. The waterproofing film must end at the level of the sealing tape.

5. A counter-lattice and a crate are mounted on top of the waterproofing material.

   

   After installing the drip and bringing the waterproofing onto it, the counter-lattice and the crate are filled

6. Long brackets for gutters are installed, fixing them to the bottom board of the sheathing, sawing into it so that there are no kinks when installing the eaves plank. They also lay a ventilation tape to protect the under-roof space from insects and debris.

   

   Long brackets and short brackets can be used when forming eaves and gutter systems.

7. If necessary, bend the bottom edge of the cornice strip in accordance with the slope of the roof with the help of an even, strong beam. Fasten the bar with nails to the first board of the stepping crate.

   

   The eaves plank is installed on top of the drip and attached to the bottom board of the sheathing

8. The lateral edge of the waterproofing film is folded up and fixed with a stapler to the extreme bar of the counter-lattice.
9. Roofing and drainage are installed.

The double structure of the eaves assembly ensures natural air circulation in the under-roof space. The air enters under the eaves and goes up into the ridge area, and condensate or accidentally ingested moisture flows down unhindered in the same way.

The double structure of the eaves assembly provides good air circulation in the under-roof space, which significantly increases the longevity of the roof and the house as a whole

Video: the correct design of the cornice node

How to make a drip for the roof with your own hands

The cornice strip and the drip (lower cornice strip) can be made independently from metal blanks. For this you will need:

• welding pliers;
• right and left scissors for metal;
• mallet and pliers;
• corner and pencil.

Work order:

1. First, the workpiece is bent at an angle slightly less than half of that on which the end is formed.
2. Next, the contours of the cuts and bends are marked with the following calculation: the length of the future diagonal + 10 mm for the hem.
3. On the lower horizontal shelf, a line is marked where the bar will bend.
4. On the longitudinal and transverse flange, the outline of the fold and bend on the reverse side is made.
5. Cut off all unnecessary and beat the fold line with a mallet along the inner mark.
6. Put the blank on the place of the future fold and wrap it up.

7. The edge is beaten off on a commensurate mandrel, the shelf is upset, the edges are pierced and the edge is folded inward.

   

   The cornice strip can be made by hand without the use of bending mechanical devices

Naturally, having a sheet bending machine, you can cope with such work much faster and easier.

Video: bending of eaves on a listogib

However, mechanical equipment can be dispensed with by following the recommendations of the tinsmiths.

Video: how to bend sheet metal at home

Blitz Tips

To properly install the drip and extend its service life, you need to use the following tips:

1. It is strongly not recommended to use a grinder for cutting the parts of the drip and eaves. Due to the speed of its rotation, the metal is heated, as a result of which the protective polymer layer burns out, without which the metal will begin to rust quickly.
2. It is advisable to use thin sheet metal for the manufacture of droppers, which is convenient to cut with scissors for metal. Manual work, of course, prolongs the production time, but it will pay off in full with the strength, reliability and long service life of the cornice assembly.
3. When buying metal plates, you should pay attention to the thickness of the metal and the presence of a protective polymer coating.
4. So that after the installation of the drip and the eaves strip there are no problems with the installation of other roofing elements, the frontal board and drainage brackets should be mounted before arranging the eaves assembly. If possible, waterproofing was laid, counter-lattice and lathing were filled, and OSB plates and a lining carpet were laid for a soft roof.
5. And without fail, once a season, conduct a survey and cleaning the drain from accumulated debris in order to increase the efficiency of its work.

Video: cornice knot - why mount two cornice strips

Reviews

When erecting a roof, every stage of the work is important. Therefore, you need to pay attention to the correct arrangement of all components, even small ones. Indeed, thanks to small-sized additional elements, such as a cornice strip and a drip, it is possible to multiply the insulating properties of the roof and ensure comfort in the house for many years.