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August 12, 2017 18:06

Wooden ceiling beams .calculation of loads

Article Contents:

  • 1 How long beams needed?
  • 2 How to load?
  • 3 beams overlap: section and step
  • 4 Economical option overlap
  • 5 Soundproofing ceilings
  • 6 protection beams from moisture and other external influences
  • 7 Protection hardwood floors on fire
  • 8 bearing capacity of beams: ways to increase
  • 9 I-joists

--- on the photo - beam ceilings , wood - house

overlapping on wooden beams.Photo

How long beams needed?

The required length of the wooden ceiling beams is determined by several moments.The beams should overlap span and have some leeway to be able to patch up their walls.If the walls are made of bricks or concrete blocks, the deepening of the beams is performed at 10 - 15 cm. The lower limit for the boards to the upper beam.Within the walls of wood indentation made by seven centimeters.

In some embodiments, the beam angles are fixed, collars and other accessories.In this case, wooden beams overlap length equal to the distance from one wall to the other.Sometimes the beam output by 30-50 cm to the outside and they are involved in the creation of the roof.

Optimal beams of wood for covering distances from two meters to four.The maximum length that can block an element from the tree - 6 m. Further, the strength is insufficient.For longer spans using variations of laminated veneer lumber or give additional support, such as columns.

How to load?

on wooden joists are constantly affected by the load consists of several components.The first term is the curb weight of all components that make up the ceiling.The second term - operational load.It can be temporary or permanent.The exact calculation is difficult, but it is possible to use a simplified version of the formula.

If the calculated load for the ceiling of the attic, which will not store anything, the constant load is taken as 50 kg / m2.

Operating load in this version will be 70 * 1.3 = 90 kg / m2.70 - the standard value for the loft, 1.3 - the safety factor.

total design load - the sum of these two, ie,50 + 90 = 130 kg / m2.Rounding and get 150 kg / m2.

These calculations assume that will be used lightweight insulation.If the materials to be used with more weight or attic will be used extensively for a variety of purposes, the characteristic load acting on the overlap is increased to 150 kg / m2.In this case, 150 * 1.3 + 50 = 245 kg / m2.This value can be rounded up to 250 kg / m2.

taken into account when creating the attic floor and the weight of the base floor, furniture, and people.As a result, the load is obtained from 350 to 400 kg / m2.

Flat - floor - in - house - with - wooden - overlaps

beams overlap: section and step

When the length of the beam is known and calculated the total load, it is possible to determine the required cross-section of this part and assembly step is to be used.

When calculating the wooden ceiling beams is taken into account that the best option is a rectangular cross-section.The height and width should have a ratio of 1.4: 1.

beam width varies from 4 to 20 cm and a height of 10 cm to 30 try to choose a height that it was convenient to lay the insulation.

On-section wooden floor beams and impact indicators such as the step with which they are stacked.Typically, step beams hardwood floor is in the range from 60 cm to 1 m.but may be varied down to 30 cm and greater up to 1.2 m. Sometimes a step selected by the plate width of the insulation material.In the framework of its buildings tied to the step frame struts for maximum rigidity.

To check the calculations and suitable online calculators are widely available on the Internet.


Economical option overlap

called A cost ceiling, consisting of wooden boards .These parts come with a covering on one or both sides.They are connected to the frame , which helps them to withstand all the loads of the vertical nature.Solid carriers are only when they are securely connected to the framework boards.Planking edges turned to shields and connected by these surfaces.Since the edges of boards and sheathing firmly connected into a single structure, they have a bearing capacity of not less than the wooden floor joists.

excellent material for building cladding are plywood and chipboard plates .Used conventional board, but they do not create overlap, having a high load-bearing characteristics.If their application is obtained a significant number of stitches having the same direction.

overlapping 11

may not be additional support elements and the gypsum boards, as well as carpentry and tsementostruzhechnye plate.The rationality of their use is low also because they are more expensive than particleboard and plywood.

Soundproofing ceilings

usually produces insulation slabs on wooden beams, but the floor decks do not require a high level of thermal insulation.Level insulation is more important factor in this case.High ceilings strength is not always matched with the required sound insulation performance.Often the floor beams in the wooden house has to further isolate , to get rid of the penetrating sounds.It is especially difficult for designers of prefabricated houses.They need to combine the two areas.It is necessary to create a structure which will be different high strength and withstand heavy loads.In this case it must be a "soft" elements that absorb sound waves.They create the best sound insulation.

beams filled with slag or expanded clay, does not meet modern standards.They do not fit the level of waterproofing or by creating technological features.

Modern standards include requirements to reduce the amount of impact noise that can be passed overlap.This sound insulation should be increased to the detriment of the ability of the supporting structure.As a result of new variants, combining indicators were created.

Steel used spring clamps.They divide the lower trim and beams, so that the impact noise transmitted smaller and faster extinguished.

11 (1 )

help improve sound insulation and special weighting inside the structure.For this purpose, sand and other materials that reduce sound transmission.

Since sand bulk material, then this is connected its main drawback.When the free dumping into the space overlap, he can wake up down through the gaps between the plates.To avoid this, the space veiled film or use special mat consisting of two layers of film between them and sand.

Instead of sand can be used in the plate cement based .Their main drawback - the high weight.As a result, the beams must be increased strength, which makes the design less economical.

impossible to ensure high sound insulation to open the bottom floors.If the beam is not sheathed bottom, and inside is not laid insulating materials, the noise level of penetration is quite high.

protection beams from moisture and other external influences

Special protection against moisture and climatic influences joists in a wooden house is not required.All construction of the attic, attic floor on wooden beams, wooden elements of the outer wall is protected in the event that the roof is made properly and not leaking.

Protect wood ceilings with special means is required only if the floor is damp on area.This may be a bathroom, sauna, laundry and any other area with high humidity.Ventilation for floors is not required.

To protect any structures fairly standard treatment.Open beams or other unventilated ceilings can be treated with paints.Special chemicals for processing are not required.

Protection hardwood floors on fire

Building materials must meet standards fire protection.All materials are divided into two groups: combustible and non-combustible.Designs are poluognestoykie and fireproof.First only delay the spread of fire, reduce the rate of fire.The latter did not burn, so do not allow the fire to spread.Flat - wooden - floor , first - floor

In a residential building, these rules should be respected as fully as possible.To ensure maximum safety .In particular floors, which are located in the seven meters above the ground must withstand fire for at least half an hour.

Since ceilings are often used wood, it is recommended to use solid wood .If we apply other wood materials, they must have a certain level of density.Often the wood is treated with special substances, fireproof combustible material.

When projected construction with exposed beams , it is necessary to take into account the impact of the fire from several sides.

To identify the structure resistance to fire use special values.For example, softwood burn speed is taken as 0.8 mm per second.

Counting design with exposed beams, allow for the necessary level of fire resistance.When the height is defined by the parameters of insulation, increase the width of the beam to increase the delay time of fire.

Questions to fire safety, as well as to sound insulation, there is still room.They will continue to be addressed in the near future all stakeholders.

bearing capacity of beams: ways to increase

to increase load-bearing characteristics of beams, used several ways.Firstly, the lining of the attached boards, increasing section.

Secondly, it can be mounted on the beam U-shaped metal profile .It also increases its rigidity and strength.


Thirdly, reduced pitch between the beams, ie,they fit much more frequently than is required.This gives a certain margin of safety, and provides freedom of action without worrying about the reliability of the design.

Periodically check the condition of overlap is necessary.Damaged beams replaced or repaired using a pad.Destroy them pests.Moisture in conjunction with decay.


Modern I-beams wooden floors are made of several materials.For their production using timber, OSB boards and coniferous wood.These beams have many positive characteristics.They are environmentally friendly, as are solely made from materials that do not emit harmful substances.I-beams are used for a long time, and thanks to the special shape and securely.They offer a unique combination of light weight and high strength.These beams do not change their geometrical parameters and does not warp.They are easy to use, since all surfaces thoroughly verified, and all the elements have the same parameters.

double-T - beam - slab

I-beam ceilings, wood beams.Photo

prices for H-beams are dependent largely on two characteristics.First - sectional area , namely, the height of the beam.Second - materials , making up the shelves.

Using I-products to speed up the construction work, sincebeams are easy to use.They will secure the house from the emergence of distortions ceilings and appearance of cracks on them, becausedo not sit down.

Using I-beams, can greatly facilitate the construction of the overlap.This bar consists of parts, which have a very small thickness and weight.However, thanks to the special design, they provide the necessary overlap for a particular level of strength.

Such beams can be manufactured to order the correct size.This eliminates the need to fit, which spends more time.

no special tools required to work with I-beams.It is quite an ordinary carpenter.The beams easily make holes, eating is required to build communications elements.

Use I-beams, not only for floors.They are used to create and truss system.