Fastening rafters to the Mauerlat: process features

The fastening of the rafters to the Mauerlat is one of the most important connections, the reliability of which determines not only the durability of the roof as a whole, but also the safety of the inhabitants of the building, since an illiterate approach to business can result in the rafter legs coming off the Mauerlat, with a further skew of the roof and even the possible fall of some of its elements to the area around the building.

Consider the technology of fastening the load-bearing elements of the roof structure and dwell in more detail on suitable fastening means for this.

Rules for attaching rafters to Mauerlat

In order to properly connect the rafters with the Mauerlat, you must strictly adhere to the following rules:

• Connecting parts to the Mauerlat and rafters are fastened securely and efficiently.
• The cuts of the rafters at the points of contact with the Mauerlat must be accurate and ensure a snug fit. At the same time, the use of various kinds of linings and other similar elements that can eventually deform, fly out, etc. is not allowed.
• Installation of rafters on the Mauerlat, fastening to other rafters, stretch marks, braces and other elements is carried out using metal corners, plates, special brackets (on the construction market you can find a sufficient number of special fasteners for rafters, for various types of connections), bolts or threaded studs .

Advice! For nuts and bolts, the use of washers or metal plates is mandatory to prevent the nut from sinking into the wood.

• In the role of overlays, as an alternative to metal plates, plywood trimmings can be used.
• Use rafter fastenings on nails or screws alone, only some time is allowed, during the installation of rafters. Subsequently, they must be replaced with fasteners by means of plates, corners and bolts.

• For wooden houses, it is mandatory to fasten the rafters sliding to the upper side logs or Mauerlat timber. In order to ensure that the rafter legs slide along the wall due to the shrinkage of wooden walls, special elements are used, the so-called "sled" ("sledge").The use of these fastening elements is not only desirable, but even mandatory, especially when it comes to covering the roof with expensive tiles or soft roofing.
• Before attaching the rafters, the lower fastening at the place where the rafters fit to the Mauerlat is subject to sawing of the so-called saddle into the rafter, which should ensure a snug fit to the Mauerlat. As a rule, they practice the execution of a template, according to which similar cuts are then made on each rafter with an identical roof angle on all its slopes. With a difference in angles on different slopes, washed down under the Mauerlat will also be different for the rafters of each slope. Washed down is usually done no deeper than ¼ of the width of the rafter.
• The fastening of the truss system to the Mauerlat should ensure that the roof is kept from being lifted by gusts of wind, as well as withstanding the load from the weight of the roof on the Mauerlat. Such fastening can be provided by using special steel corners. By a similar principle, the rafters are laid on a vertical "chair".

As for attaching the rafters to each other on the ridge, it happens end-to-end and is fixed with steel plates.

In other places where the rafters come into contact with each other, for example, on a diagonal rafter, the elements also require precise sawing (for a snug fit), fixing with corners or plates (depending on the junction) and bolting.

Recommendations for fastening the lower ends of the rafters to the building

Some pseudo-professionals mistakenly advise such methods of attaching rafters as applying twists directly to gas or foam blocks. However, stone blocks are not able to securely hold fasteners.

For example, a 100 mm nail driven into a block can be removed from there with some effort even by hand. In other words, the twists fixed in the block will not be able to securely hold either rafters, nor Mauerlat, especially when the rafters press on the structure not only vertically down, but also to the side.

It is more reliable to fasten the rafters to a brick wall or a wall made of other block material using a reinforced belt 200 mm wide and high, into which threaded galvanized studs with a diameter of at least 14 mm are attached before pouring, and in increments of 1-1.5 m.

Studs of a smaller diameter will not be as reliable, since they will bend with some effort.

To reinforce fastening truss system at the base of the studs, reinforcing crosses can be welded or a reinforced washer with a nut can be fixed.

At the time of pouring the reinforced belt, it is desirable to adjust the vertical position of the studs according to the level. This will avoid further difficulties when putting on the Mauerlat studs.

If, for any reason, the studs were inserted into the monolith at an angle, you should not despair - you just need to make a little more effort to drill holes for the studs in the Mauerlat at the required angle.

Types and features of rafter fasteners to Mauerlat

Now consider how to attach the rafters to the Mauerlat:

1. Fastening (bracket) for beams type WB - used when attaching the console of load-bearing beams in the process of installing wooden floor systems in the construction of wooden houses.

The advantages of this type of brackets are as follows:

• They do not require cutting into the carrier beam, thus, without provoking a weakening of the bearing capacity of this design.
• Do not require the use of special equipment, accessories and tools.
• Fastening is carried out with screws, nails or anchor bolts.

Such fasteners are made of sheet galvanized steel 2 mm thick.

4. Fastening of beams of separate type WBD - applicable when fastening the console of load-bearing beams of non-standard size in the process of installing wooden floors in the construction of wooden houses.

 

Fasteners have the following advantages:

• Similarly to the previous one, it does not need to be inserted into the carrier beam, which does not cause a weakening of its bearing capacity.
• As a rule, it is applicable when fastening a non-standard beam.
• The fastener is fixed with nails, screws or anchor bolts.
• There is no need to use special tools, equipment and accessories.

5. The connector is universal.
6. Bar connector.

Advice! Before you properly install the truss system, you need to determine for yourself the types of fasteners planned for use and calculate their required number.

7. Fasteners for rafters LK - used for fastening rafters and beams of the rafter-rafter system during the installation of wooden structures and roofs in the construction of wooden houses.It has the same advantages as WB fasteners, however, fastening is carried out only with screws and nails.
8. Mounting perforated tape TM - used when it is necessary to strengthen the bearing capacity of the structural unit. It is also necessary when fixing and fastening auxiliary elements.

It has the following characteristics:

• Provides reliable connection of details.
• It also does not require tie-in and does not weaken the bearing capacity of both the assembly itself and the entire structure as a whole.
• Mounted with a standard set of tools using screws and nails.

Reinforced corner KR - applicable when attaching load-bearing elements of the rafter-rafter system in the construction of wooden houses. Such a corner can both strengthen the rafters on the Mauerlat, and provide an increase in the bearing capacity of the structure.

In addition, it does not require cutting and tapping and the use of specialized equipment, accessories and tools. The corner is fastened with screws or ruffed nails.

Subspecies of corners of the Kyrgyz Republic:

• Corners KR11 and 21 are technically improved corners KR1 and 2, respectively. The use of a new (oval) shape anchoring hole can significantly reduce the risk of fastening bolt breakage during natural settlement and load of the structure. Suitable for professional builders.
• Corner KR5 - designed to connect structural parts with a greater load-bearing capacity.
• Reinforced angle KR6 - made of 3mm steel, with an oval hole that provides more reliable anchoring by reducing the risk of breaking the fastening bolt under load and natural settlement of the structure.Designed for heavy constructions, arranged by professional installers.

9. Mounting bracket KM - made of perforated steel and is applicable for attaching load-bearing and auxiliary elements of the rafter-rafter system in the construction of wooden houses.

The advantages of this corner are:

• No need for tie-in, which ensures the safety of the bearing capacity of units and structures as a whole.
• No need for special equipment.
• Fastening with nails and screws.

10. KMRP Reinforced Angle - Adjustable and applicable to any 90 degree connection. The use of stamping allows the corner to carry significant loads. The corner is designed for fastening wooden rafters to the mauerlat, and the unique horizontal hole allows the corner to be used when making a displaceable support.
11. Mortgage support.
12. Fasteners driving for racks.
13. Mounting perforated tape TM - used when it is necessary to strengthen the bearing capacity of the structural unit. It is also indispensable for fixing and fastening auxiliary elements.

It has the following characteristics:

• Provides reliable connection of elements.
• Does not require tie-in, which saves the bearing capacity of the assembly and the entire structure.
• Does not require the use of special tools, equipment and accessories.

14. Attaches with screws and nails.
15. Spiked galvanized nails with a conical head.
16. self-tapping screws

Having fastened the rafters to the Mauerlat, you can proceed to the next cycle of work - the installation of the crate, and then to the installation of the roofing pie.

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