In this article we will look at the question of how to glue wood to concrete. Sooner or later, many people who have started renovations in an apartment or house face the problem of combining these materials.
The need for gluing such materials occurs when bare concrete screed wooden is laid flooring or install skirting boards with your own hands, install wooden fillets, etc. However, sometimes fasteners are necessary for more substantial and weighty objects, and this results in additional difficulties.
Fastening methods
In the photo - installation wooden slats for installation wall panels
Behind long history carrying out construction work has been tested a large number of methods of fastening wood to concrete. Among the current and widely used methods, we note the use of specialized assembly adhesives and the use of fastening hardware.
Let's look at the features of implementing these methods and find out which materials are optimal for carrying out such work.
Application of specialized adhesives
If reinforced concrete was cut with diamond wheels, and now you have to install wooden parts that are small in size and weight, you can use special assembly adhesives.
A correctly selected adhesive composition allows you to reliably fix not only baguettes or baseboards, but also overlays. stair steps. However, you need to understand that the range of adhesive compositions is wide, and therefore you should count on the optimal result only if correct selection facilities.
If you need adhesive for concrete and wood, pay attention to the following compositions:
- Construction adhesive “Liquid nails”- it is relatively inexpensive and at the same time effective solution to work with materials of interest to us. “Liquid nails” are presented on the market in several modifications, namely, “Universal”, “Express”, “Super strong”, “Extra strong”, “For panels”, etc.
If the question is how to attach wooden block To concrete wall, best choice will become a particularly vicious and universal modification.
The universal type of Liquid Nails adhesive is an excellent choice for interior use. For example, with this method you can successfully glue wall panels made of lumber to pre-fabricated walls.
But if you are interested in how to glue wood to concrete when sub-zero temperatures, you will need “Liquid Nails” that are especially strong with a gripping force of up to 70 kg per 1 m². This glue will hold the wood even on uneven concrete at temperatures down to -17°C.
- Glue "Moment"- This is a wide range of different compositions with different technical and operational properties.
The photo shows the two-component composition “Epoxilin Duo”
Of particular interest is the “Epoxylin” modification, which is a two-component composition that works with a wide range of materials including concrete and wood.
After drying, the composition not only reliably holds the glued surfaces, but can also be sanded or subjected to other machining without compromising adhesive strength.
Another modification of the Moment glue, through which concrete can be joined to wood, is the Joiner Moment. This product has found wide application in the process of laying floor coverings made using lumber.
Polyurethane foam is a good option for simple and effective gluing
The photo shows the use of polyurethane foam
If necessary, it can be used as glue polyurethane foam increased strength. This is a good solution for flooring wooden coverings, installation of window sills, wall panels, etc.
This method of connecting two surfaces is characterized by a number of advantages, including:
- affordable price compared to other adhesives;
- high bond strength after complete drying of the composition;
- low degree of thermal conductivity, which is important when finishing floors and walls;
- excellent sound insulation qualities;
- hydrophobicity;
- biological stability;
- simple instructions for use.
However, there is also a significant drawback, namely the long drying time of the foam. Therefore, for 5 minutes the glued part will have to be held in the desired position so that it does not move away from the surface.
Important: To ensure optimal contact between the bonded surfaces and the foam, they must be slightly moistened with water.
Surface preparation is the key to success
Whichever of the above compositions you choose, before attaching wood to concrete, both surfaces must be properly prepared. In order to result installation work there was a strong and durable connection, both surfaces should be as smooth as possible, dust-free and grease-free.
The main problem is the porous structure of the material, especially if diamond drilling of holes in concrete was carried out. This property causes excessive absorption of adhesives, and therefore the connection does not have time to gain the proper strength.
It is not difficult to make a coating from concrete that is predisposed to gluing; to do this, you need to reduce the number of pores. Primers are used for this deep penetration, which seep into the porous structure of the material and solidify there. As a result, the micropores close, and the density of the concrete allows the use of glue.
Important: Wooden parts should be glued to pre-prepared concrete bases in strict accordance with the adhesive manufacturer’s instructions.
Fastening using dowels
If you need high-quality and durable fastening of a wooden pole to concrete, ordinary glue or foam is not enough. In this case, you can use fastening hardware, designed for high mechanical loads.
Heavy wooden parts can be attached using dowel nails and anchor bolts. The principle of operation of these fasteners is similar, since after they enter the concrete, their working part begins to burst. As a result, fastening wooden poles to a concrete base it turns out to be very durable.
Conclusion
There are many ways reliable connection concrete surfaces With wooden parts, but maximum strength will be guaranteed if preliminary preparation is carried out. There is no need for it if a connection using dowels is used.
More educational and useful information you will find by watching the video in this article.
Wooden logs are required to ensure natural ventilation underground space and better heat retention in rooms. Thanks to the use of logs, the floor covering can last much longer. However, among people without great experience in the construction business, you can often hear the question whether it is necessary to attach the logs to concrete floor? Experienced craftsmen know that for a truly durable flooring that does not change its geometry under load, and for its long service life, it is imperative to correctly fix the logs on any supporting structure, including on concrete screed.
Now that it is clear whether it is necessary to attach the joists to the concrete floor, it is worth noting that this task is not difficult, does not require special skills and knowledge, and, therefore, can be done by any home craftsman.
- Materials and tools
- Fasteners
- Tips for choosing lags
- Tools
- Methods for installing joists on a concrete floor
- Fastening the log to a metal corner
- Attaching joists to concrete pillars
- Step-by-step instructions for attaching joists to concrete with your own hands
- Step between joists
Materials and tools
Fasteners
The question of how to secure joists to a concrete floor has different answers: simple or adjustable designs. The latter use special screws, by tightening which the logs can be leveled. In addition, the choice of fasteners and fastening methods depends on what kind of joists are used.
Most often, the lags are fastened to the concrete floor with metal anchors or self-tapping screws with polypropylene dowels, the dimensions of which are selected depending on the cross-section of the selected beam for the lags.
The choice between anchor nails or self-tapping screws is determined by the following:
- Self-tapping screws are cheaper, of course, but anchors are more reliable. In practice, fastening with self-tapping screws is almost always sufficient.
- The advantage of anchors is that in addition to fixing the beams, they tightly press the logs to the base. This becomes especially important when the finishing coating is quite heavy and is regularly exposed to mechanical stress - this must be taken into account when choosing the method of how to properly attach the joists to the concrete floor.
At modern technologies logs under wooden floor it would be possible not to fasten it at all, however, such a solution would greatly increase the likelihood of the floor covering being skewed or the joist being displaced from its original location. Therefore, when it comes to fastening lags, it is best to rely on old methods that have been time-tested more than once.
However, fastening may not help if low-quality or unsuitable lumber or incorrect fasteners are chosen for the work.
When choosing logs for a concrete floor, you need to pay attention to the following points:
- type of wood;
- type of lumber;
- length and section;
- price.
For reasons of economic feasibility, you should not take expensive wood, because spruce, fir or pine are correct processing can last no less. Doesn't have special significance And appearance material, however, it is necessary to discard specimens eaten by grinders or blackened by mold. Evenness of tone and correct geometry of the lag are of less importance. For this work, grades B and BC with a humidity not exceeding 20% are suitable. As is customary to work with lumber, they should be stored in a dry room for some time so that they equalize the humidity with the surrounding atmosphere.
All wooden elements Before attaching the joists to the concrete floor, you need to thoroughly soak it with an antiseptic.
Tools
Since the task is how to lay logs on a concrete floor, you will have to use the following tools in your work:
- Drill and hammer drill.
- Carpentry tools: a circular saw, hacksaw, plane.
In addition, you will have to spend money on waterproofing, which must be spread over the entire surface of the concrete. When calculating the amount of material, you need to add another 10-15 cm overlap to the floor area.
Methods for installing joists on a concrete floor
Methods for attaching joists to a concrete floor come down to four main options, after familiarizing yourself with which, any master can choose the most suitable one for himself.
This the simplest way fastening the lag, but, unfortunately, it is not suitable in every situation.
- First, you need to drill holes in the timber to match the diameter of the plastic dowel, and use a hammer drill to make a counter hole in the concrete.
- Then the dowels are driven in with a hammer, after which self-tapping screws are screwed into them or dowel-nails are driven deep into the ceiling.
- The head of the screw should sink a few centimeters into the hole.
People often ask, what step of attaching the joists to the concrete floor is better? There is no strict standard here - the step can vary from 40 cm to 80 cm, but on average you can safely focus on half a meter.
The logs will hold securely enough only when there is a small gap between the base and the beam. This should definitely be taken into account by those who want to know how to properly lay joists on a concrete floor.
Anchors, unlike self-tapping screws, not only rigidly fix the logs, but also attract them to the concrete surface. Thanks to this installation wooden beams will hold more securely, which is why most craftsmen prefer to use anchors. In addition, this powerful fastener will restrain the deformation of the wood to a certain extent, especially if it has not been sufficiently dried beforehand. But it is much more difficult to pull an anchor out of a concrete base than to drive it in, so workers will have to spend a lot of effort during dismantling.
Be that as it may, when using anchors, the floor covering will not swell, but it may sag. To avoid the latter, it is necessary to install gaskets more often.
- Installation of logs on a concrete floor here begins with drilling through holes in the beam.
- Then, opposite each of them, counter holes are made in the concrete.
- After that anchor bolt inserted into both holes and tightened with a spanner or open-end wrench. It is important not to overtighten the bolt, otherwise it will bend the beam, especially when there is a gap in this place. Then and on finishing field there will be a depression here.
Before installing the anchor, you need to drill a larger diameter hole in the beam to accommodate the bolt head.
The anchors should be spaced at intervals of 60-100 cm, and their length should be sufficient for them to penetrate approximately 6 cm into the concrete. Most often, anchors with a diameter of 10 mm are used. Typically one joist is held in place by 4-5 anchors.
Video about attaching joists to a concrete floor with anchors:
Fastening the log to a metal corner
It becomes inconvenient to work with logs 10 or more centimeters high. To fasten them, it is better to use steel corners, which will touch the joist with one shelf and the concrete base with the other. Fixation in in this case It is done: to concrete - with dowels and nails, and to timber - with self-tapping screws. In this case, the main load should fall on the gaskets, and not on the fastening elements, because the corners should only fix the position of the beam.
In order for the lag to be better bonded to the surface, you need to use self-tapping screws whose threads do not reach the head.
You can also attach wooden elements to a concrete base using a galvanized steel corner. The installation process is as follows:
- Attach the corner to the joist using self-tapping screws, which should go at least 30 mm into the wood.
- Attach the corner to the concrete base using dowels.
Video on how to secure joists to a concrete floor with corners:
There is another option for attaching joists to a concrete floor. For this, a rectangular stand is used, which is attached to the base with four dowels. In the middle of this stand there is a pin that pierces the beam through and through.
By rotating the nut located under the beam, you can accurately set its height, and use the upper nut to fix the element in the required position.
This system is not that difficult to install; it is attached to the floor with dowels, and you will need to make a hole in the joist for a pin. The frequency of installation of stands under it depends on the cross-section of the log; however, in any case, it is not recommended to make an interval of more than 1 meter. This option of attaching the logs to the concrete base, although recognized as optimal, however, due to high cost didn't become too popular.
After fixing the logs, a subfloor made of boards, OSB or similar materials is laid on them. If the work is done efficiently, the appearance of the finished floor can be impeccable.
Attaching joists to concrete pillars
Logs are attached to concrete pillars in the same way. The same fasteners are used here, but intended for poles.
- The pillars need to be waterproofed in advance by coating them with simple bitumen or bitumen mastic. The upper cut of the pillars can be waterproofed by placing pieces of roofing material pre-cut according to its configuration on it.
- Also, in advance, you need to make holes in the bases of the pillars and in the timber into which to drive a dowel or anchor spacer.
- The beam is attached to the post with a self-tapping screw, the length of which is 2-3 times the width of the spacer.
- The timber can also be attached with special metal plates equipped with screws. For this purpose, they are screwed to the base of the posts with dowel nails, and a through hole is drilled in the joist, into which you will then need to insert a screw and screw the joist to the top of the posts. Thanks to this, the lag will hold tighter.
Step-by-step instructions for attaching joists to concrete with your own hands
Attach to concrete floor wooden joists It's not difficult even on your own. There are several mounting options, and below are the steps of one of the standard methods.
- Lay waterproofing (roofing felt or plain film from PVC). The joints between the pieces must be secured with special tape.
- Next, you need to lay out the logs along the floor in a certain step. This step will depend on the material from which the finishing flooring will be made: when using a 25x100 mm tongue and groove board, the logs can be laid with an indent of 70-80 cm, but for other materials the step will need to be reduced to 40 cm.
- If the length of the material is not enough to cover the entire room, then the elements can be joined using an iron angle or by making cuts that form a connection into a root tenon.
- Before installing the joists on the concrete floor, you need to take care of the outermost joists that will be located near the walls. They must be laid level, clearly leveling their height by placing them under the beams wooden planks or pieces of plywood. Most convenient to use laser level. When the outermost logs are fixed, a nylon thread is stretched between them, which will serve as a guide when installing the remaining logs.
- To attach timber to a concrete floor, you need to make holes in both. You need to drive a dowel or steel anchor spacer into the hole in the concrete. Each joist must be fixed with at least four anchors, and the screws must be placed 40-60 cm from each other.
- You need to prepare levelers for the joists in advance - cut chipboard or plywood into even strips. With the help of these elements, the joist structure is fixed in a level position (pieces of plywood are simply placed under the joists if you need to raise them) so that the finishing coating on it does not creak or move.
- If in concrete base If, on the contrary, there are bulges, then you will have to level the lag not by placing plywood under it, but by selecting part of the material from below using a plane.
- When all the logs are installed in their places, thermal insulation should be laid between them, for example, expanded clay.
- Before covering with the topcoat, you should think about laying the necessary communications. It is also advisable to use a vapor barrier layer.
Step between joists
How to properly lay joists on a concrete floor, if for finishing coating will be used different materials? Below is the relationship between the thickness of the floor boards and the distance between the joists:
- with a board thickness of 20 mm, there should be a distance of 20 cm between the logs;
- for boards 25 mm thick, a step of 50 cm will be required;
- for 25 mm – 60 cm;
- for 40 mm – 70 cm;
- for 45 mm – 80 cm;
- for 50 mm – 100 cm.
If the floor is plywood, then the step between the joists is determined differently:
- with a plywood thickness of 15-18 mm, a lag pitch of 40 cm is required;
- at 22 mm – 60 cm.
Which method do you prefer to attach joists to a concrete floor, and why? Share your opinion or experience in the comments.
Wooden building material, despite its fragility, is constantly used in buildings. Used as a base for fences, decoration of extensions, as foundation parts. During work, the tree must be periodically attached to the concrete. Many questions immediately arise: how to properly install wooden poles, how to extend their durability? Answers to them require preparation.
general information
At first glance, the situation is complicated, but there are tricks that help you cope with the work without much difficulty. Before you begin installation, you should choose what kind of wood the future base will be made of and carefully process it. Wood processing is an important process, because when exposed to environment she's spoiling.
Processing is carried out on the prepared post. The support is divided into two halves, each of them is treated differently chemical preparation. The part that is underground is more susceptible to moisture; it is treated with bitumen-based solutions twice, maintaining an interval of a day. The second part of the post is usually coated with varnish, protecting the wood from wind, sun and moisture.
Important! Before processing, the wood must be dried, and careful sanding will help save bitumen impregnation.
Installation methods
After completed preparatory work let's move on to installation. We mark and prepare the place for the supports. Options for installing poles are determined by the design features and the nature of the work. Installation means concreting a support or fixing it to concrete. There are main methods:
- universal concreting of the base;
- use of concrete stepson;
- installation on concrete;
- use of frame;
- special connection;
- platform with a box.
Versatile method - concreting
Installation of wooden poles using concreting is well suited for soils with high humidity. The installation method assumes preliminary preparation holes for the base, installing pillars in them and filling the remaining space with concrete.
To increase efficiency when digging holes, the ground is watered; the ground becomes soft and easy to work with. With a pillar height of 1.5 m, the depth for the hole is 0.5 m, for more high depth increase to 0.8 m. The pillar is deepened by 1/3 of its length.
When the groundwater level is high, the supports are deepened below the soil freezing level and the bottom of the holes is covered with a layer of crushed stone up to 15-20 cm, which acts as drainage. The bottom of the supports is wrapped with roofing felt, fired, and treated with resin to better protect the wood.
Having completed the preparation, they begin to compact the holes. The holes are filled with crushed stone, pieces of brick mixed with soil, and compacted tightly. We leave 15-20 cm to the top of the hole, and the empty space is filled with concrete. After the solution dries, the pole holds tightly and will not bend under the load. The joint between concrete and wood is treated with a sealant, which prevents moisture from getting between them.
The second way to install a wooden pole is to use a concrete stepson. The essence of the concreting procedure is to use not the entire column, but a small column. The sequence of the procedure is as follows:
- before installation, the support is treated with an antiseptic, the part of the stepson that will be in the ground is covered with bitumen and wrapped with roofing felt;
- crushed stone is poured onto the bottom of the hole;
- vertical fixation of the support with spacers;
- Be sure to fill the wooden post with crushed stone, gravel and compact it well. Maintaining a compaction interval (every 30 cm), adding sand and water will help increase the density of the backfill;
- 15-20 cm to the top, the hole is filled with a concrete solution, which ensures stability.
After the concrete has hardened, it is necessary to secure the log with wire to small posts.
Wooden posts and racks are the main element of most structures of canopies, gazebos, pergolas, fences and other light structures on the site. We'll tell you how to install them correctly so that they last as long as possible.
Often, a pergola or fence has to be repaired only because the wooden poles on which they are supported, buried in the ground, have rotted and become lopsided. To avoid such unpleasant phenomena, it is necessary to install wooden poles on anchors.
This applies even to poles after autoclave impregnation, not to mention those independently treated with bioprotective preparations. In this case, contact of the pillars with the ground is eliminated, which significantly increases their service life.
But if you bury the pillars themselves in the ground (which is much cheaper and less labor-intensive), then you should protect the wood from the effects of moisture contained in the soil. So, after installing the post, it is better to fill the hole not with excavated soil, but with gravel.
For additional protection the lower part of the post in the ground surface area can be wrapped with film or roofing felt.
Gate posts subject to high loads should be concreted.
All these protective measures concern only the lungs wooden structures- fences, small gazebos or pergola.
Racks and poles for them can also be installed above the ground - for example, on U-shaped load-bearing shoes (anchors) made of galvanized steel. Anchor rods made of corrugated steel rods are poured into pits with concrete or cemented into ready-made concrete plinths.
All wooden posts that bear high loads, for example on the roof of semi-open garages, extensions for winter gardens, should be installed on heavy anchors. The most common among them are H-shaped anchors, designed for racks with a thickness of 70-140 mm. Anchors are placed in holes and filled with concrete or cemented into the holes of finished concrete plinths. There are anchors of other designs.
1. After installing the stand, it is better to fill the hole with gravel rather than with excavated soil.
2. Before installation, the stand in the part that will be in the ground and slightly above it is treated with bioprotection agents and wrapped with film or roofing felt. The upper edge of the film is secured with perforated tape, staples or nails.
3. The protruding edges of the film or roofing felt can be covered with pieces of boards for greater reliability. The latter are treated with bioprotection agents and screwed to the rack.
4. Wooden gate posts should be concreted in holes measuring at least 30 x 30 x 60 cm. Above the ground level by a width concrete pouring It is advisable to make a small blind area with a slope from the rack.
5. Widely used anchors for fastening poles and racks: at the top left - a light anchor with a width of 71 mm, next to it - an anchor with an adjustable width up to 141 mm, to the right - a heavy anchor with a tubular rod and an anchor with two jumpers 600 mm high, at the bottom - two anchors attached to the base with bolts.
6. Ready concrete plinths. For the construction of lightweight structures, plinths with a height of 30, 40 or 50 cm are used, for heavy ones - with a height of 60 or 80 cm.
7. When installing an anchor in a plinth, install the plinth in the ground, and then insert the anchor rod into the hole, placing pieces of timber under the anchor as temporary support. After this, the anchor is filled with mortar.
8. Heavy anchor under the rack pitched roof suspended on two bars with a cross-section of 35 * 35 mm and a length of 60 cm above the foundation pit, after which they are filled with concrete.
9. Place a stand in the anchor, level it and secure it with a clamp. After that they drill through holes and secure the stand with bolts.
10. On the right are concrete plinths 80 cm high with a cavity for heavy anchors. On the left - ready-made concrete blocks with anchors built into them.
11. Anchor made of galvanized steel with a base for fastening with dowels and bolts to a concrete slab.
12. The rack is placed in the anchor, leveled using a level, then secured.
Taking into account wind loads
For the construction of simple wooden structures, lightweight anchors are quite suitable. However, this only applies to posts for garden fences up to 1 m high, free-standing pergola posts and other lightweight structures. When erecting structures subject to high wind loads, for example screen walls with a height of about 180 cm, only heavy anchors should be used, including those mounted in concrete plinths.