Preparatory work for laying floors on joists. DIY frame house

You have control over every aspect of the project, including the floors, when you build your own frame home. It’s a rewarding endeavor. One essential step to ensuring your floors are level, strong, and long-lasting is to lay your floors on joists. Although this task may seem difficult, you can accomplish it on your own if you prepare ahead of time and have the necessary equipment.

Prior to beginning the floor installation process, there are a few crucial steps that need to be taken. You can make sure your floor is installed correctly and steer clear of common pitfalls by following these steps. An effective project requires careful planning and preparation.

We’ll walk you through all of the necessary prep work in this guide so that you can install floors on joists in a do-it-yourself frame home. We will cover all the necessary information to get you started, from choosing the appropriate supplies to organizing your workspace. Together, we can successfully complete your flooring project!

Floor construction on joists

It will be easier to understand which floor components we are discussing if we first take a schematic look at what makes up the floor on the joists.

Putting in floors on lags

Selecting material for flooring on joists

The choice of floor material depends primarily on personal preferences and requirements for the floor in terms of aesthetics, environmental friendliness, speed of installation and of course cost. So, if you have decided on choosing a material for a floor made of natural wood, then a suitable covering is a board (grooved or not tongue-and-groove). If the floor is planned to be covered with something, for example, laminate, then you can also consider the options of laying plywood or OSB along the joists instead of boards. The minimum thickness of plywood for flooring is 12 mm with a lag pitch of 30 cm. The minimum OSB thickness is 18 mm with the same lag pitch (30 cm).

Based on firsthand experience, tongue and groove boards are typically utilized for covering floors on joists; therefore, we will examine this specific type of flooring in more detail in this article.

Choosing the type of wood for coating

-Pine, spruce, fir – the boards from which are most often suitable for floors with light loads, since these materials are quite soft, dents are easily made on them. If you decide to lay a floor made of these materials in rooms with high traffic and load, then you need to try to treat the coating as carefully as possible and not walk on it in thin heels. This material is not suitable for wet areas. -Aspen and alder are medicinal wood species, so they are suitable for the bedroom and children"s room. -Oak is a dense and durable wood, it costs more, but a floor made from such a board will be very strong and durable. -Siberian larch is as hard as oak, thanks to resins, Siberian larch boards practically do not rot, so they are suitable for any floors, including those with high humidity, for example, for a bathhouse. But they are 2-3 times more expensive than pine. Also, alder, birch, beech can be used for floors in a bathhouse.

Spruce is generally not advised for use in plank flooring because it is an excessively soft wood, and linden and poplar are only appropriate for non-residential spaces.

Although oak and larch floors cost more than pine floors, the floor created from them will benefit not only the owner but also their grandchildren (assuming that’s a goal). However, if you don’t need the board to last 100 years before needing to be replaced, go with a pine board that will last 50 years. Naturally, with appropriate maintenance and installation.

Grooved or not tongue and groove board

Board with tongue and groove. Joining a rectangular tongue and groove installation (tongue and groove)

There is no tongue-and-groove on the board. straight-edged butt joint

Common non-groove boards are used to lay the floors that have cracks and uneven surfaces found in older homes. So, you must realize that this is exactly how the floor will look in a few decades, regardless of how perfect the geometry of the new, non-grooved boards may be. A board that isn’t grooved and composed of sturdy wood like oak or Siberian larch might be the sole exception.

Consequently, a non-groove board made of low-cost wood species like pine, spruce, or fir is only appropriate for subfloors, or floors that will have coverings placed over them. You must use a tongue and groove board for a finished wooden floor. board with tongue and groove

This floor is entirely different from what we are accustomed to seeing in older homes, with its cracks, imperfections, uneven surface, etc.P.).

Floor board thickness and size

Primary board measurements

Board gauge thickness

Boards come in thicknesses from 20 to 40 mm. Often, when choosing the thickness of the board that they intend to lay on the floor, they are guided by the principle – the thicker the board, the stronger the floor. In this case, you should remember that wood is a natural material that tends to shrink and at the same time it (the wood) moves a little, twists. So if, for example, you take a 40 mm board for a floor that has not been properly dried in drying chambers, but is taken raw, as a rule, since it is cheaper, then such a board will behave very harshly during natural drying. It might even tear out the self-tapping screw that secures it. And at the same time, the same not sufficiently dried board of smaller thickness (22, 24 mm) will behave much better, the mass is smaller, the strength of the mass is less, and accordingly it does not tear out the screws. Therefore, the most practical thickness of the floor board is 22, 24 mm. If you take a thicker board – 30, 40 mm, then it should be dry, dried in drying chambers to a moisture content of 10%, maximum 12%.

Board breadth

There are also variations in the width of flooring boards: 100, 120, 140, and even 200 mm. Similar to thickness, you must base your decision on the wood’s moisture content. You can take a wide board (150–200 mm) when the board material has a moisture content of 12%; however, it is preferable to take an under-dried board that is narrower, measuring 100 mm. 100 mm is the most widely used board width.

Board measurement

Boards on sawmills are sold in lengths that are multiples of 1 meter, t.e. 3, 4, 5 and 6 m. It doesn"t get any longer. If the boards are planned to be laid offset, then, in principle, the length does not matter much, and you can order a shorter board, it is a little cheaper, but the laying method itself is more labor-intensive, there are many joints. If the boards are laid without displacement, then it is ideal, of course, to take the board along the length (or across the width of the room). So, for example, for a room measuring 7×4 m – 4 meters long, and for a room 4×3 m – 4 or 3 meters long.

There are two ways to lay floorboards: a) with displacement, b) without

Kind of tree

The purpose of the board covering—whether it is finished or rough—as well as one’s financial situation and the type of top floor covering—varnish, paint, or wax—will determine the type of wood used to make the board.

Excellent quality. These types of boards are the best quality, but they cost more. Not everyone enjoys knots, so they should be completely free of them. It’s entirely a personal preference. Ideal for coating with transparent materials like varnish, wax, or oil, which reveal the wood’s structure. Such pricey boards are useless for coatings like paint. superior grade boards

First class. board with knots of live light. The best choice for coating with transparent compounds that show off the wood’s structure in terms of quality and cost.

Second class. On the boards’ surface, there are numerous knots that are visible, some of which are dead, dark knots. This is a great way to paint a floor because the knots won’t show through.

Third level. The boards are noticeably curved, have bad geometry, and are covered in knots—some of which occasionally fall out. Although this board is substantially less expensive, its installation—which includes adjusting, trimming, and sanding—will cost more and take longer. Because special trimming and sanding are not required, such a board is a good choice for utility and technical room floors. Board 3 grades

Temperature of Humidity

We know that the ideal option is a board dried in special drying chambers on a sawmill to a humidity of 12%. Such a board must be transported and installed in dry weather, not in fog or rain. A more economical option is not dried board, humidity 18-20%. It needs to be installed as quickly as possible. T.e. on the day of delivery be ready for installation, have the appropriate tools and already installed floor joists. If you do not plan to do the installation yourself, then hire a team of workers to lay the floor on the day of delivery. If you don’t lay them down right away, they will begin to dry out, twist, or blow out in an arc. All this ultimately leads to losses, since such a board will have to be sanded, which can be avoided by laying it right away.

Method of laying boards

Boards are typically laid in bedrooms and bathrooms in the direction of the light coming in from the windows and in high-traffic areas like vestibules and hallways in the direction that people move.

Orientation for laying floor boards

Insulation for floors on joists

If we are talking about the floors of the first floor, then they must be insulated always and without exception. The floor on joists need not be insulated only if the floor borders below with a heated room. To insulate the floor on joists, vapor-permeable insulation, such as basalt mineral wool or fiberglass wool, is best suited. In floors on joists, the insulation does not carry a load, so soft positions with a density of 30-50 kg/m3 are suitable. The thickness of the insulation depends on the region in which the construction is located, usually it is not less than 150 mm, but in some cold regions, the thickness reaches 200 mm, so the thickness of the insulation must be calculated by a specialist.

Putting in hardwood floors on joists

Type, quality, and humidity of wood. Most frequently, cheap solid pine, spruce, or fir logs are used for flooring; less frequently, more costly larch wood, grades 2-3, with a humidity of 18–20%, is used.

Choosing the Lag Section

The logs should have a rectangular cross-section, with a height to width ratio of roughly 1.5 to 2. Logs are most effective with this cross-section.

Section lag. Ideal height to width proportion

The span on which these logs will be laid primarily determines the cross-section of the logs. In this instance, the span is the separation between the lower frame beams that the logs will rest on.

Additionally, the thickness of the insulation (hut) that must be placed between the logs will determine the cross-section of the logs, or their height, as shown in the figure below. And keep in mind that there needs to be a ventilation gap of hvent = 2-3 cm between the floorboard and the upper edge of the insulation. Additionally, the insulation will be installed below on the roll-up (hch), which is fastened to the joists and positioned atop the cranial block (hch.b.).

Consequently, the following formula is used to determine the minimum log height: hlag=hch.b.+hroll+hut+hvent.

Hut is determined for a particular area;

– hvent = 2-3 cm.

Space for ventilation between the board and insulation

By placing intermediate supports, or support columns underneath the logs, the span can be decreased without having to lay pricey logs with a large cross-section.

Installing a support column beneath the logs as an intermediate support will reduce the span.

The cross-sections of logs for various spans are shown below, assuming that the logs are laid no more frequently than every 70 cm. Step latency

Your given sections will have a very small margin if your lag step is less than 70 cm.

(section of span – lag)

• 2 m – 110×60 mm;
• 3 m – 150×80 mm;
• 4 m – 180×100 mm;
• 5 m – 200×150 mm;
• 6 m – 220×180 mm.

It is preferable to take the lag section with a margin, i.e., such that it fits the next larger span, when the span has an intermediate value. Only in very rare cases—when the floor is covered in thick boards measuring more than 40 mm—is a lag pitch greater than 70 cm allowed. Consequently, we do not take into consideration sections of logs laid with such a large pitch (800-1000 mm) within the context of this article.

Installing intermediate support pillars in increments of two to one meter beneath the logs makes sense. 1-1.2 meters is ideal. In this instance, the lag sections will be as follows:

(step between the support pillars; log cross-section)

• 2 m – 110×60 mm;
• 1.5 m – 100×50 mm;
• 1.2 m – 90×50 mm;
• 1 m – 80×50 mm.

While a larger lag cross-section can be taken, a smaller one is not recommended. You can therefore use logs of a larger cross-section than necessary, for example, without risk.

Lag time in steps.

The thickness of the floor covering determines the step at which the logs are laid; the stronger the covering, the fewer times the logs need to be installed, and vice versa; if the coating is thin and not very durable, then more times the logs need to be laid.

The suggested lag pitches and various floor covering options are shown below.(Lag pitch – board thickness)

• 20 mm – 30 cm;
• 24 mm – 40 cm;
• 30 mm – 50 cm;
• 35 mm – 60 cm;
• 40 mm – 70 cm;
• 45 mm – 80 cm;
• 50 mm – 100 cm.

Support pillars for joists

The brick used to mount them is grade M 100. The statement that sand-lime brick cannot be used on support columns is frequently made in writing. Only regions with high groundwater levels—that is, those that are less than two meters below the surface—can claim this. Then using red brick is preferable. Red and sand-lime bricks work just as well in other situations.

Sealing the floor’s joists with water

Positioned on a brick in front of the joists for extra protection as well as on the foundation to stop groundwater from rising through capillaries. The thickness of the waterproofing determines how many layers are needed. Thus, one layer of waterproofing will suffice if it is 3 mm thick; if it is thinner, two layers will be needed. Roofing felt is not something we advise using, but if you do have it on hand, it should be applied in two to three layers for standard waterproofing.

Soundproofing floors using joists

Impact noise is reduced with the use of soundproofing pads. They are positioned right beneath the logs on roofing felt. They should extend about 1 centimeter past the joist’s edge on each side and be marginally bigger in size than the joist’s thickness. For example, the soundproofing lining should measure 120 by 120 mm for a joist that measures 100 by 150 mm (width by height).

Lining with soundproofing. The extent of the overhang behind the joists

These linings can be composed of a range of materials, including leftover plywood, OSB, chipboard, antiseptic wooden boards, cork backing, special compensation tape, or a foamed polyethylene backing (similar to that found under a laminate, but thicker). For such a substrate, the recommended thickness is 1-4 cm.

In order to ensure a sturdy and level foundation, there are a few essential steps to take before laying floors on joists in a do-it-yourself frame home. Examine and level the joists first, making sure they are evenly spaced and firmly fastened. To improve soundproofing and thermal efficiency, place insulation in between the joists. Installing a moisture barrier at the end will shield the subfloor from moisture and provide a solid foundation for your finished flooring. By taking meticulous measures in preparation, you can build a sturdy floor that will increase the comfort and longevity of your frame home.

Foundation for floor posts on joists

To create a foundation for the posts, a tiny quantity of concrete will be required. Depending on what is more practical, this foundation can be shared by one line of columns or distinct for each column. distinct foundation for every pillar of support

A common foundation strip connecting every row of pillars

Step	Description
1. Site Preparation	Clear the site of debris and vegetation. Ensure the ground is level.
2. Foundation Installation	Lay a solid foundation using concrete or treated wood. This will support the joists.
3. Joist Layout	Mark the positions for joists on the foundation, maintaining equal spacing.
4. Joist Installation	Secure the joists to the foundation using metal brackets or screws.
5. Subfloor Preparation	Cut and fit the subfloor panels to size, ensuring they fit snugly over the joists.
6. Subfloor Installation	Attach the subfloor panels to the joists using nails or screws. Ensure panels are level.
7. Moisture Barrier	Install a moisture barrier over the subfloor to protect against dampness.
8. Final Inspection	Check the entire structure for stability and ensure all joists and panels are securely fixed.

Careful planning is essential when installing floors on joists in a do-it-yourself frame home. Your floor will have a sturdy foundation if the joists are level and firmly fastened. Before moving forward, take some time to look for any anomalies and make the required corrections.

Your floor’s stability and longevity can be greatly affected by using the appropriate supplies and equipment. Select high-quality lumber and adhere to suggested joist spacing and securing procedures. Long-term, this attention to detail will save you money and time by preventing problems.

Take your time installing the vapor barrier and insulation. These actions are essential for preserving energy efficiency and shielding your house from issues caused by moisture. A comfortable living space will also be enhanced by properly installed insulation.

And lastly, put safety first at all times. To prevent mishaps, put on the proper safety equipment and abide by the rules. You can improve the overall quality of your frame house with a solid and dependable floor that you create with careful planning and execution.

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