Do-it-yourself extension to the house from foam blocks

Do-it-yourself extension to the house from foam blocks Extension to the old house from foam blocks - how to make it right

An extension to an old wooden house made of foam blocks is an excellent method to increase the living space or to combine the utility room that has the main structure. This decision is economically justified, because one wall will already be ready.

Often they add a terrace, garage, summer kitchen or even a winter garden. And if you approach the matter thoroughly, it is additionally important to insulate the walls, equip heating, then a full-fledged living room can be used in the winter season.

The extension is a small part of a private house, but when building it, you must follow the same rules as in the main construction.

Arrangement of the base, roof, masonry, exterior decoration, which protects the structure from external influences, requires a competent and responsible attitude. The durability, as well as the strength of the structure, will directly depend on the high quality of work.

What is important to know before starting construction from foam blocks

Any construction needs to start with design, and for this it is important to determine:

  • Purpose of the object ...

  • Required dimensions of the extension - width, length and height.
  • Placement in relation to home.
  • Structures and materials from which you plan to build.

It is important to draw up a detailed drawing indicating the dimensions in the plan, the location of door and window openings, the marking of communications. The best option would be to develop the project by professionals, because this document will be required for further processing.

Before you start building an extension to the house, which will be made of foam blocks, it is important to find out the type of land - whether you have a heaving soil, its depth of freezing. It is also important to determine the type of foundation for the existing building. We recommend laying the same foundation for the structure as for a private house - pile, columnar or tape. It is required to take seriously the design of a major remake. It will be easier to do this before the start of construction work, since otherwise it will be necessary to coordinate documents through the court for a long time.


Which houses can be attached to

Extensions made of polystyrene concrete or foam concrete blocks can be attached to brick, wooden, block or even frame type of house. there are no restrictions on the composition of the material.

Please note that the main requirement is that the existing structure should in no case be dilapidated, and its foundation should be very solid. The attached structure will create an additional load on the ground, and it can also cause unwanted shrinkage of the foundation of the old house, and also lead to its destruction.

There are two ways to carry out an extension:

  1. On an independent foundation - with heaving soil with a high occurrence of water, it will be more expedient to erect a building in the form of a separate structure.

    This helps to avoid cracks, as well as the appearance of deformation due to seasonal ground movements. The joint between the two types of structures is a small gap that is filled with waterproofing material.

  2. On the basis, which is rigidly fastened to the foundation of the house, reinforcement. The structure is a monolithic mass on which the building and annex will be supported. This option is suitable for slightly weeping soils, and the occurrence of water will be at least 2-2.

    5 meters.

Next, you should consider in more detail all the pros and cons.

Advantages and disadvantages of concrete blocks

Foam concrete blocks are made of foamed concrete by molding from a semi-liquid type solution or by cutting a solidified mass of foam concrete. The composition, in addition to the standard cement, sand and water, will include a foam generator. Thanks to him, the structure of the material will acquire lightness and porosity, so an extension to the house from foam blocks with your own hands will be an ideal option.

Foam concrete blocks are used in private construction for building partitions, walls, insulation of load-bearing structures. The material will have the following characteristics:

The disadvantages include:

  • Foam concrete is very hydrophobic, namely it absorbs moisture from the environment.

    This reduces its thermal insulation properties, and therefore the external walls must be protected by finishing.

  • Not the highest frost resistance, it can be F15-F75. This will mean that it can withstand 15 to 75 freeze and thaw cycles without strength changes and destruction. For comparison, high-frost concrete has the F300-F1000 grade.

On the basis of foam concrete, the following varieties are made - polystyrene concrete, arbolite, gas silicate, expanded clay concrete (particle-type concrete) and fiber-reinforced concrete.

They have a porous structure, high thermal insulation properties, and sufficient mechanical strength. The room, which is made of such materials, has a favorable microclimate due to vapor permeability and environmental friendliness.They are much easier to handle with tools - sawing, drilling and attaching staples.

Preparatory stage and planning

The preparatory construction stage includes works on cleaning and leveling the site. It is important to cut and transfer the soil layer for use in gardening needs.

It is important to allocate a place for storage of building materials, transport entrance. Communications should not in any way interfere with construction, and therefore they are temporarily turned off or even transferred to a safe area. There must also be permissions from the relevant organizations. Calculations are required on the basis of pre-drawn drawings, the need for main building materials, as well as products. Purchase and store at the designated location.

It is important to place the base with a cord, pegs and rags before lining up on a prepared site. It is important to check the geometry using a construction tape or special devices - a theodolite or laser level. The diagonals must be equal.

How to make an extension with your own hands (main stages)

Consider the main stages of construction will include:

  1. Earthwork - you need to dig a trench, holes or even drill wells under the base according to the selected design solution. It is desirable that the private house and the extension have the basic type of foundation, material and the same depth of laying.

  2. The base for the walls of an extension to a private house made of lightweight foam blocks is sufficient to deepen by 0.7 meters. At the bottom of the pit, it is required to pour a cushion of rubble and sand, and also to compact. Install reinforcing frames, pour concrete. Pile foundations are assembled by a special organization using professional equipment.

    Columnar are laid out from blocks, bricks, or even pipes are deepened into the ground with a further concreting process. Waterproof the top of the structure with rubemast, roofing felt or bikrost.

  3. Bricklaying should be carried out with the dressing of the seams similar to the brick. In the role of a binder, a cement-sand mortar and plasticizers are used, a frost-resistant tile or even a specialized adhesive for foam concrete. On the top of the wall, prepare a reinforced concrete belt that can hold the structure together and also give the required degree of strength and stability.

    The joint between the main wall and the extension is reinforced with embedded elements, brackets with rigid adhesion, and to create a deformation-type seam, it is filled with expanded polystyrene, elastic tapes, silicone / bitumen / acrylic compounds.

Jumpers must be installed above the openings. Here the following is used:

  • Ready-made reinforced factory reinforced concrete or even aerated concrete beams.
  • U-shaped elements made of aerated concrete with a recess for concrete and reinforcement.
  • Monolithic lintels, which will be made at the construction site in the formwork.

  • Steel corner.

It is important to limit the maximum opening width to 1.75 meters and the minimum support depth to 0.25 meters. Photos of foam block extensions to the house are attached as an example.

Construction of ceilings and roofs, decoration of the facade

After the strength of the concrete reinforcing belt is gained, it is required to install an extension overlap. They make ready-made panels from lightweight concrete or make a structure from boards and beams. You can pour a monolithic slab or even create a beam system and deck with increased thermal insulation parameters. the roof of the annexes is usually pitched.

It is made of a rafter system (rafter legs, Mauerlat, lathing and flooring) and a "pie" of the roof.

In the role of a coating, the same or even a material similar in characteristics is usually used as the coating of the main structure. When installing the roof, it is important to ensure that there are no leaks at the joints with the roof of a private house. for fastening, elements of a sliding type (sled) or sliders are used.

It is they that will help maintain the mobility of the roofing sheet during sedimentary deformation. It is important to pay special attention to the external type of decoration, because it helps to protect the foam concrete from premature destruction, and also gives the house with the extension a finished look.

Various types of facade cladding can be used:

  • Do-it-yourself extension to the house from foam blocks Panels and slabs for outdoor finishing.
  • Materials of natural origin - stone or wood.
  • Decorative panels for brick or stone.
  • Plaster.
  • Siding.

Along with the installation of finishing materials, walls can be additionally insulated. For this, the following building materials are used:

  • Glass wool.
  • Foamed polyethylene.
  • Penoplex.
  • Mineral wool.

  • Expanded polystyrene.

Insulation boards are placed between frame guides, protecting, if necessary, steam waterproofing. It is important to install finishing elements outside. You can clearly see the attachment of an extension to a foam block house in the video.

The cost of an extension to a turnkey house

The exact price of work on installing an extension to a private house cannot be said immediately, because many factors must be taken into account here, including type of base, condition of the soil and the house.

if we start only from the price of materials, then the dependence of the cost on the dimensions will be as follows:

Extension dimensions, m Cost , rub (from)
2 * 4 110 000
6 * 2 175,000
6 * 3 255,000
7 * 3 278,000
4*6 316,000
7 * 4 368,000


The cost of building an extension from foam blocks to a brick or wooden house is quite affordable, and in return you can get additional square meters of garage, housing, a bathhouse , a veranda - this will increase the convenience and comfort of the previously built house. the main thing is that you contact a competent construction company. In this case, you will have a guarantee of the quality of the work.

( 5 marks, average 2.2 out of 5 )