The article contains a detailed description of the technology for building a brick arch. A step-by-step instruction with video tutorials will help you understand the main points of the calculation, preparation and laying of the vault. You will learn how to correctly assemble the formwork and avoid mistakes during its installation.
An arched vault or lintel is an effective solution to the appearance and a reliable construction of the top of any opening. Due to its greater length (compared to a straight lintel), it distributes the load better, which makes it possible to do without the use of metal or concrete when erecting walls or cladding. Scope of the arch structure made of bricks:
- Structural wall openings.
- Brick cladding.
- Fireplaces, stoves (hearth or firebox).
- Street barbecues and barbecues.
- Free-standing portals (wicket, gate).
To build an arch, you will need advanced skills of a bricklayer and carpenter. If you are not confident in your abilities, it is better to lay out a test structure, evaluating its stability. We will consider the option of creating an arch using an abstract example..
To work, you need the following tool:
- Mason’s set – pickaxe, cord, trowel, buckets.
- Power tool – grinder, screwdriver, jigsaw.
- Carpentry measuring and marking tools.
Preparation for work
For masonry of the arch, it is necessary to assemble a temporary bearing formwork from wood (bar, rail, sheet material). This is a wooden support that follows the shape and dimensions of the inner plane of the arch. In order to do it, you need to know the following parameters of the future design:
- The shape of the vault. In total, there are two types of arched vaults – a regular arch and an arched lintel. You can learn more about them in the article “Window lintel”. In the work itself, the chosen form does not play a big role, so here you should be guided more by a combination of appearance with other architectural elements.
- Arch radius. In a regular arch, the radius of a semicircle (vault) is half the distance between the supports (along the inner plane). The radius of the arch of the beam lintel is determined arbitrarily (individually) for reasons of appearance.
- Distance between the inner planes of the supports. Determined locally. The circle should pass freely between the supports.
- Wall thickness. The arch can be of any thickness, even a continuous tunnel. To begin with, we recommend building a structure with a thickness of 1 brick (250 mm).
- Advance paynemt. The main condition for the stability of a brick lintel is an odd number of bricks. That is, the central (“castle”) stone should be at an equal distance from the supports or their projections. If it is slightly less than the standard, you can cut it with a grinder. In this case, the thickness of the seam in the lower part of the masonry must be at least 5–6 mm, in the upper part no more than 30 mm.
When all dimensions have been removed and there is complete clarity of the desired result, you can proceed to the assembly of the formwork.
Assembling the formwork
- Cut out two identical semicircles or a segment according to the dimensions of the future arch from sheet material (OSB, plywood, chipboard) (masters call these segments “circled”).
Attention! At this stage, we recommend spreading the arch on the ground and making sure that the preliminary calculation is done correctly.
- Screw the bars to the circles for reinforcement – along the bottom and in the upper third (horizontally, parallel).
- Fix the walls at the required distance (250 mm) with a bar.
- Distribute the slats with a step of 200 mm along the edge of the circle so that they form a supporting frame. Fix them with self-tapping screws.
- Thin sheet material (plywood, OSB 4–6 mm, galvanized, fiberboard) to cover the working plane of the formwork (the place where the bricks are laid). The wooden plane can be greased with oil or diesel fuel so that it does not deteriorate from the solution, and it is easier to remove the formwork.
The formwork is ready. Now you need to install it directly in the opening..
Even if the weight of the bricks is supposed to be small, and the arch is at a height, we strongly recommend installing the formwork on vertical posts. They can be fixed to the supports with dowels in the seam, and an additional support can be placed in the middle. Be sure to make struts.
As a rule, the arch is laid out simultaneously with the plane, therefore the place of the “heel” (the support area of the arch arch) is determined by the level of the masonry row. Its height must be known in advance (within tolerance).
If you decide to make an onion (segment) jumper, you will have to additionally lay out the stops for the heel. For this, the brick is cut in place. The shape of the trim is according to the position of the first brick of the vault. In this case, the formwork is installed so that the beginning of the arch falls on the plane of the heel.
Arch masonry and heel trimming, video
The vaults of a regular arch begin with a brick lying horizontally, then rise, gradually changing the angle of inclination. Therefore, the formwork should be installed after placing the first brick in the support. The beginning of the vault will fall on it (on the first brick).
The arch is not much different from the ordinary masonry – the main difficulties are associated with the correct calculation and manufacture of a flat formwork. If you are making a “cold” arch, use a reinforced proportion of cement mortar (1 part cement, 2.5 parts sand). If it is going to be a stove or barbecue, you should use a special solution on clay.
The brick is laid on the formwork from both sides at the same time. Use the thickness guides of the bottom layer and check the flatness. It should coincide with the plane of the supports, and the joints are filled with mortar. You can dismantle the circles no earlier than 21 days from the moment of installation.
Outdoor fireplace – video of masonry walls and arches
Having mastered the main principles of calculation, formwork creation and the general approach, the novice master develops his own techniques and know-how. The more practice, the better the result will be. Based on the data in this article, you can master the laying of any kind of stone lintels.
Arch-shaped firebox. Step-by-step video with comments