What to make roof joists from. Fastening and laying the floor on joists
Laying the floor on the joists is done independently. Ease of installation and a number of advantages make this material indispensable for flooring. What determines the popularity of lag?
Firstly, the load on the floor (structure or ceiling) is distributed evenly along the entire perimeter. Secondly, laying the floor with lags means providing the interior of the apartment with heat and sound insulation properties.
Some benefits
Laying the floor on joists has the following technical features:
- Thanks to the free space that forms the log, communication can be carried out.
- It is possible to raise the floors to the required level or level them.
- The floor finished with lag is distinguished by its structural strength. The beams can withstand up to 5 tons of weight.
- Installation does not require any special skills. construction industry. You only need tools and accessories.
- Logs are characterized by their low cost. If you plan to do the installation yourself, you will save money.
What is lag? These are beams made of wood or polymer that are laid on a finishing surface. The versatility of such a beam is determined by the fact that it can be mounted on a wooden, reinforced concrete and earthen base.
What are the joists made of? The log is a beam that is made of metal, wood, plastic, reinforced concrete. However, wooden ones are especially popular.
Return to contents
Construction and arrangement of logs
If the surface is made of wood, then a smooth surface will be difficult to achieve. To get the smoothest floor possible, you should attach the floor joists to the side joists. Usage this method does not require a special lining that regulates the height of the bars. The logs must be fastened with screws, which must be 2.5 times longer than the width of the beam with a diameter of at least 6 mm.
To avoid the formation of cracks in the wood, experts recommend making a hole in the beam and joist with a diameter of 2.5 mm smaller than the diameter of the screw.
If there is a large distance between the beams, repeated laying is required, which is perpendicular to the first laying. However, the distance should be less. Another option is to use thicker boards designed for finishing.
If you have concrete floors, then the floor structure with joists looks completely different:
- It is necessary to foresee the location of the waterproofing in advance. It will provide the floors with warmth and resistance to dampness.
- The next step will be the placement of heat and sound insulation layers.
- A dry or cement screed is required.
- Finally, the logs are laid. The finishing coat is laid down last.
For such work, you need boards at least 2 m long. If this length is not enough, then you can join the parts end to end. When the logs are connected, you should take into account one important circumstance: the joints of adjacent boards should be shifted relative to each other by half a meter.
The beams can be laid either on a screed or on waterproofing. Otherwise, the log will absorb moisture, which will shorten its service life. It is not recommended to lay joists on soft insulation. Gradually, you will notice how the floor will deteriorate, ruining the finished floor. When installing thermal insulation, you can use boards of a certain width, but the beams must be located strictly between them. In any other case, the work will be in vain and will not bring the desired result.
If the insulation is longer than the beams, then select the location of the logs so that the distance between them can be filled with scraps. This is a very economical solution, since you do not have to buy additional lags.
If you want to lay timber on an earthen base, then you should prepare the surface. First remove the turf, then spread 5cm of gravel over the surface. The final stage will be pouring 5 cm of concrete on the floor. After this, apply waterproofing, screed, and insulation. In addition, if you are working with an earthen base, then the screed and insulation can be replaced with polystyrene concrete.
Now about the distance between the lags. It should be no more than 40 cm so that the load is evenly distributed on the floors.
Adviсe correct installation lag:
- Before work, the surface should be thoroughly cleaned. You should also apply a primer.
- The wood must be treated with a special solution. You can use an antiseptic, for example, bitumen. This is done in order to prevent mold and rot from occurring on the boards.
- Sound insulation can be made from sand, chipboard or slag.
- The bars are installed exclusively along the window; the gap between them and the walls should be no more than 4 cm.
- After installation, you should check the evenness of the surface according to the level (rule). There should be no gaps or gaps between the beams and the tool. If they are not there, then you did everything right. If gaps are found, you should pour sand into the space or, conversely, remove it.
Return to contents
How to lay a floor: step-by-step instructions
To make your own floors with joists, you need to develop a plan. In the plan you can indicate the parameters of the beams, all kinds preparatory work and accessories that will be useful during the installation process.
Tools required for work: hammer drill, drill, wrench, hammer, jigsaw, axe.
You will need:
- Axe.
- Rule (or level).
- Hammer.
- Jigsaw (or saw).
- Drill.
- Screwdriver.
- Claw hammer.
- Wrench (size: 13-14).
- Board.
- Logs (dimensions: 50×50 mm).
- Insulation.
- Anchor bolts 1 cm.
- Self-tapping screws 5 cm.
- Nails 7 cm.
The beams are laid at a pre-calculated interval between them for sound insulation. A level should be used to ensure the surface is as level as possible. If the surface is concrete, then anchor-type bolts are used to fasten the logs. If the base is made of any other material, then dowels are used.
What are the advantages of wooden joists?
The technical properties of the beams are determined by strength, reliability, and ecology.
Lag does not require any additional care. In addition, floors on joists have a presentable appearance.
The advantages of lag include:
- no effort is required to make the floor level;
- the beams have thermal insulation properties;
- installation is done quickly, in several stages;
- excellent sound insulation;
- possibility of locating communications.
Return to contents
Laying thermal insulation
As described earlier, logs are mounted with a certain step. Insulation (super-thin basalt fiber or expanded polystyrene) is placed in the remaining gaps. You can use it for these purposes roll insulation. In addition, expanded clay can be used for the insulating layer.
The rafters serve as the basis for the entire roofing structure, and their installation is one of the most important tasks when building a house. The frame of the future roof can be made and installed independently, observing technological features roofs different configurations. We will present the basic rules for the development, calculation and selection of a rafter system, and also describe the step-by-step process of installing the “skeleton” of the roof.
Rafter system: rules for calculation and development
Rafter system - Basic structure, capable of resisting gusts of wind, taking on all external loads and evenly distributing them onto the internal supports of the house.
When calculating truss structure The following factors are taken into account:
- Roof angle:
- 2.5-10% - flat roof;
- more than 10% - pitched roof.
- Roof loads:
- permanent - total weight all elements " roofing pie»;
- temporary - wind pressure, the weight of snow, the weight of people carrying out repair work on the roof;
- force majeure, for example, seismic.
The amount of snow loads is calculated based on the climate characteristics of the region using the formula: S=Sg*m, Where Sg- weight of snow per 1 m2, m-calculation coefficient (depending on the slope of the roof). The determination of wind load is based on the following indicators: type of terrain, regional wind load standards, building height.
Coefficients, necessary standards and calculation formulas are contained in engineering and construction reference books
When developing a rafter system, it is necessary to calculate the parameters of all components of the structure.
Elements of the truss structure
The rafter system includes many components that perform specific function:
Materials for making rafters
Rafters are most often made from trees coniferous species(spruce, larch or pine). For roofing, well-dried wood with a humidity level of up to 25% is used.
The wooden structure has one significant drawback- over time, rafters can become deformed, so metal elements are added to the supporting system.
On the one hand, metal adds rigidity to the rafter structure, but on the other hand, it reduces the service life of wooden parts. Condensation settles on metal platforms and supports, which leads to rotting and damage to the wood.
Advice. When installing a rafter system made of metal and wood, care must be taken to ensure that the materials do not come into contact with each other. You can use moisture-proofing agents or use film insulation
In industrial construction they use metal rafters, made of rolled steel (I-beams, T-beams, angles, channels, etc.). This design is more compact than wood, but retains heat less well and therefore requires additional thermal insulation.
Choosing a rafter system: hanging and suspended structures
There are two types of rafter structures: hanging (spacer) and layered. The choice of system is determined by the type of roof, floor material and natural conditions region.
Hanging rafters rest solely on the external walls of the house, intermediate supports are not used. Rafter legs hanging type perform compression and bending work. The design creates a horizontal bursting force that is transmitted to the walls. Using wooden and metal ties you can reduce this load. The ties are mounted at the base of the rafters.
Hanging rafter system often used to create an attic or in situations where roof spans are 8-12 m, and additional supports are not provided.
Layered rafters mounted in houses with an intermediate columnar support or additional load-bearing wall. The lower edges of the rafters are fixed to external walls, and their middle parts are on the inner pier or supporting pillar.
Installation of a single roofing system over several spans should include spacers and layers roof trusses. In places with intermediate supports, layered rafters are installed, and where there are none, hanging rafters are installed.
Features of arranging rafters on different roofs
Gable roof
Gable roof, according to building regulations, has an inclination angle of up to 90°. The choice of slope is largely determined by the weather conditions of the area. In areas where heavy rainfall prevails, it is better to install steep slopes, and in areas where strong winds prevail, flat roofs are installed in order to minimize the pressure on the structure.
Common option gable roof- design with an inclination angle of 35-45°. Experts call such parameters the “golden mean” of consumption. building materials and load distribution along the perimeter of the building. However, in this case attic space It will be cold and it will not be possible to arrange a living room here.
For a gable roof, a layered and hanging rafter system is used.
Hip roof
All roof slopes have the same area and the same angle of inclination. There is no ridge girder here, and the rafters are connected at one point, so the installation of such a structure is quite complicated.
It is advisable to install a hip roof if two conditions are met:
- the base of the building is square in shape;
- in the center of the structure there is a load-bearing support or wall onto which a post supporting the joint can be fixed rafter legs.
Create hip roof it is possible without a stand, but the structure must be strengthened additional modules- stand-up puffs.
Hip roof
Traditional design hip roof assumes the presence of slanted rafters (diagonal) directed towards the corners of the building. The slope angle of such a roof does not exceed 40°. Diagonal runs are usually made with reinforcement, since they account for a significant part of the load. Such elements are made from double boards and durable timber.
The joining points of the elements must be supported by a stand, which increases the reliability of the structure. The support is located at a distance of ¼ of the length of the large rafters from the ridge. Shortened rafters are installed in place of the gable roof gables.
The rafter structure of a hipped roof can include very long diagonal elements (more than 7 m). In this case, it is necessary to install under the rafters vertical stand, which will rest on the floor beam. You can use a truss as a support - the beam is located in the corner of the roof and fixed to adjacent walls. The truss truss is reinforced with struts.
broken roof
Sloping roofs are usually created to accommodate a larger attic. The installation of rafters with this roofing option can be divided into three stages:
- Installation of a U-shaped structure - supports for purlins that hold the rafter legs. The base of the structure is floor beams.
- At least 3 purlins are installed: two elements pass through the corners of the U-shaped frame, and one ( ridge run) is mounted in the center of the attic floor.
- Installation of rafter legs.
Gable roof: do-it-yourself rafter installation
Calculation of inclination angle and loads
Calculation gable roof Of course, you can do it yourself, but it’s still better to entrust it to professionals in order to eliminate errors and be confident in the reliability of the design.
When choosing the angle of inclination, it is necessary to take into account that:
- an angle of 5-15° is not suitable for all roofing materials, so first choose the type of coating, and then calculate the rafter system;
- at an angle of inclination over 45°, material costs for the purchase of components of the “roofing cake” increase.
Load limits from snow exposure range from 80 to 320 kg/m2. The design coefficient for roofs with a slope angle of less than 25° is 1, for roofs with a slope from 25° to 60° - 0.7. This means that if there are 140 kg of snow cover per 1 m2, then the load on a roof with a slope at an angle of 40° will be: 140 * 0.7 = 98 kg/m2.
To calculate the wind load, the aerodynamic influence coefficient and wind pressure fluctuations are taken. The value of the constant load is determined by summing the weight of all components of the “roofing cake” per m2 (on average 40-50 kg/m2).
Based on the results obtained, we find out the total load on the roof and determine the number of rafter legs, their size and cross-section.
Installation of Mauerlat and rafters
Do-it-yourself installation of rafters begins with the installation of a Mauerlat, which is fixed anchor bolts to the longitudinal walls.
Further construction of the structure is carried out in the following sequence:
Installation of rafters: video
Methods for connecting rafter structure elements: video
Currently, the construction industry is developing rapidly, new products are constantly appearing on the market good materials. But, like many years ago, the use natural wood remains relevant. A floor covering based on logs can be installed quickly, the price of the logs is quite reasonable, and all that remains is to figure out how to correctly lay the floor logs with your own hands, since this will significantly reduce the cost of the work.
Preparing the base
Most often, the floor on joists is arranged on concrete base or in private houses directly on the ground. Instructions for each method are given below.
Construction on a concrete basis
Installation on concrete base given time occurs most often.
- The first thing to do is prepare the screed. The difference in height across the horizon is too of great importance doesn't have it here. So, with a difference of up to 40 mm, you can adjust the horizontal position of the logs using pads under the logs. If the difference is more serious, it is recommended to fill it with a more even one.
cement-sand screed on the floor.
Cement floor screed: composition, properties, installation" href="https://shkolapola.club/ustroystvo/styazhka/608-cementnaya-styazhka-pola">cement-sand screed on the floor.
Float:="" none="" margin:10px="" center="">
Arrangement on the ground
- Before laying floor joists on the ground, you should prepare the ground itself. The distance from the ground level to the logs must be at least 160 mm.
- First you need to remove the first fertile layer of soil.
- In its place, a cushion of crushed stone or sand is filled and compacted.
- Next, waterproofing is laid over the entire area, which will be discussed in more detail below.
- Next, you should install brick support columns under the logs or pour in a small, reinforced, strip foundation directly under the bars.
- Support posts or strip foundations are made in increments of 30 cm to 1 m. Depending on the thickness of the finishing coating, the thicker and more powerful the coating, the wider the step can be taken.
Installation of logs
- Before installing the floor joists, the timber should be thoroughly treated with an antiseptic so that it does not absorb moisture and is not eaten by pests. From experience, the most best option, this is to impregnate the timber with mining machine oil, and several times. This method does not produce foreign odors and reliably protects the timber.
- You should also not use freshly cut timber. The moisture content of the timber should not exceed 18 - 25%. Because later, when drying, the logs can lead and your floor will become deformed.
- Next, you should set the horizon level according to upper level lag To do this, using a large building level, at a convenient height, draw a horizontal line along the walls along the perimeter of the entire room.
- After that, we lower this line using a tape measure, ruler and pencil to the required height.
- Next, you should lay a layer of waterproofing. The most optimal material in terms of price/quality ratio is polyethylene from 200 microns. The waterproofing is laid in strips overlapping by 200 - 300 mm and taped.
- After installing the waterproofing, we make support columns. If it is soil, then you can use a brick, plus a reinforced cement-sand cushion on top of the column.
- If it is a screed, then the supports can be made from plywood squares, which should also be treated with an antiseptic, glued or tightened with self-tapping screws.
- Each beam is exhibited separately. The first beam is placed at a distance of 200 - 300 mm from the wall. Further depending on the thickness of the finishing coating.
Table for calculating the cross section of the logs and the step between them.
- We should not forget that if you are planning to lay a floorboard, it is customary to lay it in the direction from the light source, that is, from the window. Consequently, the logs themselves will be located perpendicular to the direction of laying the boards. The same goes for laminate flooring.
- Further, if the distance from the timber to the base is large enough, it can be filled with expanded clay. This material quite light, plus provides good thermal insulation and sound insulation. The price of expanded clay is quite affordable.
- If the beam has no big gap between the floor, that is, practically lying on the screed, it makes sense to use mineral wool mats or expanded polystyrene sheets for insulation. Calculate the thickness of the insulation depending on the cross-section of the timber. Ideally, the insulation should be tightly laid flush with the top cut of the timber.
Laying the finishing coating
- Before you lay the floor on the joists, you should decide what kind of coating you will have.
- If you are using parquet or laminate, you will need to lay a level on top of plywood sheets with a thickness of 10 mm or more; you can use chipboard or OSB.
Parquet or laminate, then you will need to lay a level on top of plywood sheets with a thickness of 10 mm, you can use chipboard or OSB.
Important: batten must be well dried, the moisture level of the forest should not exceed 12%. Otherwise, the board may move during the drying process and your floors will be damaged.
When laying linoleum, parquet or laminate, you will need to lay a level on top of plywood sheets with a thickness of 10 mm or more; you can use chipboard or OSB.
Important: the floorboard must be well dried, the moisture level of the forest should not exceed 12%. Otherwise, the board may move during the drying process and your floors will be damaged.
How to lay linoleum correctly: sequence of work and important nuances» href=»https://shkolapola.club/elast/linoleym/ukladca/279-ukladka-linoleuma»>lay linoleum, parquet or laminate, then you will need to lay a level on top of plywood sheets with a thickness of 10 mm or more, you can use chipboard or OSB.
Important: the floorboard must be well dried, the moisture level of the forest should not exceed 12%. Otherwise, the board may move during the drying process and your floors will be damaged.
It's up to you to decide, the main thing is that it is dry.
Conclusion
Installing a floor on joists, as you can see, is not very difficult. Almost any owner who knows how to use plumbing and carpentry tools at the household level can install such a structure. And on our website you will always be provided with detailed instructions.
The video in this article clearly shows the process of installing logs.
You want to make a roof yourself, but don't know where to start. In principle, every person understands that the roof is an integral part of the house. That is, without a roof, a house is not a home.
Do-it-yourself construction will help you not only gain experience, but also save a lot of money.
After all, almost half of construction costs goes to pay hired workers. And only when you do the roof yourself can you be one hundred percent sure of the quality of the work performed.
The structure must be light, since it puts pressure on the walls and foundation, and at the same time strong, so that it can withstand the weight of the roof and a large amount of precipitation and strong winds. The roof is a construction kit, so to speak, which is best assembled by a company of three people (more are possible).
The basis of the roof is a frame, which consists of straps. The straps are installed on the ceiling joists. A ceiling joist is a beam that is fixed to the walls and, after covering with boards, forms the ceiling in the house and the floor in the attic. If you do not plan to use the attic as a room, you can use bars measuring 50 × 150 millimeters.
And if you decide to make yourself an attic, then use beams for ceiling joists 150 × 150 mm. If the house is brick, it is advisable to use maurlat. This is a beam that is fixed to brick wall, around the entire perimeter of the house. It is attached using studs pre-installed into the wall or armored belt.
For straps used in construction use edged boards size 50 × 150 millimeters. The logs are displayed in the form of a hut (letter Λ). First we put it along the edges or brick gables. These will be the templates according to which we will make all other lags.
The frequency of lags depends on the material from which the roof will be made. From the two installed straps we pull three cords (at the top along the ridge, in the middle, at the bottom). The straps extend beyond the outer part of the wall by at least 30 cm; the larger the extension, the less precipitation will fall on the walls.
Then we install all the rest, securing them with braces or sheathing boards. Next, we place a support beam in the middle of each strap. If the roof is attic, the support can be moved slightly to increase the usable space.
We place the top of the straps end to end with each other and embroider them at the top with a block (if the roof is attic, we fix the block at the height of the desired ceiling). All fastenings should be made using self-tapping screws.
We fasten the straps to the joists using metal staples. After the straps are set, we cover the top with lathing. For the sheathing, an inch board is used, or an unedged one. Just remove the wane from the boards (bark along the edge of the board). We lay waterproofing on the sheathing.
And already for waterproofing with a stele roofing material of your choice (slate, tiles, etc.). For construction, use dried lumber.
The floors are constructed in several layers. The part visible after finishing the floor installation, which primarily performs a decorative function, is the finished floor. Underneath there is a rough foundation, on the correct installation of which depend quality characteristics floors: sound insulation, absence of squeaks, thermal insulation, evenness, etc. The classic version of the rough foundation is a floor on joists. It is their arrangement that will be discussed.
Logs are beams laid across the room, on top of which a finished floor or a finishing wooden floor is laid. The beam can be made of metal, polymer materials or concrete. But most often wooden logs are used. The installation principle is approximately the same for lags made of any material.
Arranging the floor on joists has a number of advantages:
- ease of execution and the ability to replace elements if necessary;
- the presence of space between the joists makes it possible to lay thermal insulation, communications, and with this design, ventilation of the subfloor is ensured;
- creating a flat surface for the main floor;
- uniform distribution of load on the floor;
- robust design.
Among the disadvantages, one can highlight the susceptibility of wooden joists to moisture, as a result of which the geometry of the floor changes, as well as the appearance of squeaking. But you can reduce the likelihood of these problems occurring correct installation observing all the nuances.
Features of installation of logs
You can install floor joists yourself. The main thing is to follow certain rules.
First you need to choose a material that won’t put a big dent in your budget. At the same time, the logs must perform their functions well. Ideal option are beams made from coniferous trees, as they are impregnated with resin, which provides additional moisture resistance. Larch is expensive, so pine, spruce or fir beams of the second or third grade with a moisture content of about 18% are more often used.
The timber for the logs should have a rectangular cross-section, and the width should be approximately 2 times less than the height. The greater the distance between the support points for the logs, the larger the cross-section of the beams should be:
- for a two-meter span, the height of the log should be 11 cm and the width - 60;
- for three-meter - 15x8 cm;
- 4 m – 18x10 cm;
- 5 m – 20x15 cm;
- 6 m – 22x18 cm.
Note! When choosing the section of the log, take into account the width of the insulation layer, from which there should be 3 cm to the floor for ventilation.
The distance between the logs should be on average 50-60 cm. If thick boards are laid on the logs, then the distance can be increased to a meter. For a tiled floor, the joists should be installed at a distance of 30 cm from each other.
From the first and last joists to the wall, leave a distance of 2 cm, which is filled mineral wool. According to the rules, logs are laid across the room.
Wooden floor elements must be treated with antiseptic agents.
These are the general nuances of installing subfloor joists, regardless of the base on which the beams are laid.
Instructions for installing joists on the ground
When laying logs on the ground, they are supported not only by the grillage or beams of the lower frame of the house, but also often by special posts that will need to be prepared. They are built after the soil has been prepared. But first we will describe the process of erecting support pillars.
The pillars are made of brick. But first the foundation is prepared.
Installation of logs on the ground
The installation of the logs itself includes the steps described below.
Step 1. Level and compact the soil.
Note! It is recommended to remove the fertile layer, replacing it with a compacted layer of gravel and sand, 10 cm each.
Step 2. Install the support pillars according to the scheme described above.
Step 3. Lay the first pendulum logs against the walls and 2 m from each other.
Step 4. Check with a level whether the beams lie horizontally relative to each other and relative to the ground. If necessary, where the joists sag, you can insert pads, and trim the bulging areas with a plane. Such adjustments can only be made if there is a deviation of 1 mm per linear meter lag
Step 5. Lay the remaining beams, checking them with a level.
Step 6. Attach the logs to the posts and beams metal corners and screws. At this stage, the installation of the joists is completed, and the installation of the remaining parts of the subfloor or finishing boards begins.
Laying joists on concrete floors
Laying and alignment of lighthouse logs: 1 - finished floor level; 2 - lags; 3 - soundproofing gasket; 4 - level; H - thickness of the plank covering
Installation of logs on concrete floor– this is an option not only for private houses, but also for apartments. The entire installation process is simpler than for laying joists on the ground and includes the following steps.
Step 1. Thoroughly clean the surface of the ceiling from debris.
Note! If the slab is uneven, it is sometimes poured concrete screed or produce sand bedding.
Step 2. Polyethylene is first laid on the concrete as waterproofing, and the edges of the film should extend 10 cm onto the walls.
Step 3. Mark the places where the joists will be installed on the walls.
Step 4. Where the logs will lie, lay a noise-insulating layer of soft chipboard or sand-slag embankment.
Step 5. As when installing logs on the ground, first lay the beacon logs. Mounting wedges are placed under all the logs, including the first ones, which will allow the beams to be leveled.
a — leveling of the level of intermediate lags; b - displacement of the joints of laid joists; c - control of laid logs;
1 — lighthouse logs; 2 - intermediate lags; 3 - soundproofing gaskets; 4 - control rail; 5 - half-wood joint; 6 - the same back to back; 7 — level
Step 6. Lay all the logs, level them, and fix the wedges with the beams with screws.
Note! Sometimes logs are laid on the floor without wedges and attached to concrete base corners. The masters do not have a common opinion.
Installing joists on beams
In some cases, logs are installed at wooden beams ceilings and fixed to them. The installation is the same as in the cases described above, and begins with the installation of beacons. Sometimes the floor beams themselves act as joists if the distance between them does not exceed 60-80 cm.
The methods of laying lags described above are classic options. However, in Lately Adjustable floors, in the joists of which have special holes for fasteners, which are racks with bolts, are becoming increasingly popular. The racks themselves are secured to the base using anchors.
This design greatly simplifies the installation process, including adjusting the floor level using a key and fastener bolts.
Adjustable joists virtually eliminate the appearance of squeaks and improve floor ventilation, but increase the cost of the floor, as it requires very high-quality components.
In conclusion, let’s say that no matter what option you choose for installing joists, the right approach you will receive a high-quality and environmentally friendly subfloor. The main thing is to follow the rules and carefully carry out all work on laying the logs.
Video - DIY floor joists. Laying joists on concrete
Video - Installation of subfloor from logs