- Excavation and ground planning
- Substrate under the blind area
- Installation of curb stones
- Waterproofing under the blind area
- Which tile to choose
- Laying procedure
If you find the flat concrete blind area around the house too boring, there are no barriers to laying it with paving slabs. Of course, such a coating causes a number of difficulties, but they are all surmountable. We will tell you about the technical details of the device of the paved blind area in the step-by-step instructions..
Excavation and ground planning
In order for the blind area not only to serve as an aesthetic addition to the house, but also to protect the supporting layer of soil under the foundation, it should be arranged only after careful preparation of the base. An integrated approach at this stage will ensure a high durability of the coating, exclude uneven subsidence and compensate for the effect of frost heaving.
Blind area scheme: 1 – soil; 2 – foundation; 3 – clay castle; 4 – geotextile; 5 – gravel; 6 – waterproofing; 7 – sand preparation; 8 – geotextile; 9 – paving slabs; 10 – border
The width of the blind area is on average 50% of the depth of the foundation, taking into account the preparatory layer, but not less than 60 cm.After stepping back from the base to the width of the blind area and about 5 cm more, you need to hammer in wooden pegs and pull the lacing. A fertile soil layer is removed along it, then the bottom of the trench is cleaned up and leveled so that its overall level is 30 cm below the lowest planned point of the finished coating.
Please note that if the blind area will be performed with a slope, it must be formed by a layer of backfill. Thus, after excavation, the bottom of the trench should be in a common horizontal plane. When the bulk of the soil has been removed, a 10×10 cm depression should be dug along the outer edge of the blind area.
Substrate under the blind area
The most difficult task is to properly organize the outflow of water and ensure the safety of the waterproof layer. The first preparation layer is a soft, oily clay, homogeneous and free of inclusions. The bottom of the trench is covered with a layer of up to 50 mm, and a recess along the edge is also filled. Clay does not serve as the main waterproofing agent, but it prevents water from flowing in the opposite direction. As a result, the surface should have a slope of about 2–3 cm / m to the outside, while the clay itself should be thoroughly tamped down, after soaking it with water.
After the clay layer has dried, roll out needle-punched geotextiles over it and fill it with 15–20 mm fraction with a total layer of 7–10 cm. If the blind area requires a longitudinal slope, it is set precisely by the gravel substrate.
Spread another layer of geotextile on top of the rubble and fill with washed sand. The final level should be lower than the finished coating by the thickness of the paving slabs plus 20-30 mm. With a layer of sand, the longitudinal slope of the blind area is finally displayed, plus a transverse slope towards the ground of the order of 3: 100 is set.
As the sand is poured, it must be carefully tamped and spilled with water, achieving the highest possible density. The finished surface must be carefully drawn with a rule, the tolerance is only 3-5 mm.
Installation of curb stones
When the plane of the sand and gravel bed is carefully leveled and compacted, you need to plot the estimated width of the blind area from the base, using a wooden plank with a nail as a thickness gauge. Along this line, a layer of sand is cut with a spatula and the unnecessary residue is thrown onto an adjacent soil area. The result is a groove 100-150 mm deep, into which the curb stones will be installed.
It is preferable that this stage of work takes place in dry weather. When installing curb stones, it is advisable not to walk on the bedding so as not to bring down the groove undercut. The curbstones are installed along a common cord, indicating both the distance from the building and the height of the installation. Usually stones are placed on the sidewalk principle, that is, flush with the main surface.
For height alignment, fine gravel should be poured into the curb groove and carefully tamped. The distance in width should be such that a gap of 15–20 mm remains between the cut edge of the bedding and the body of the curb.
Paved pavements do not differ in absolute water resistance, part of the water inevitably seeps through them. To remove it, it is necessary to install stones with laying of sleeves from a sewer PVC pipe with a diameter of 50 mm. At the junction of the stones, their edges should be trimmed with an abrasive wheel, when inserted, the sleeve is fixed in place with cement mortar. Places for the installation of sleeves are optimally located below the level of the adjacent ground.
Waterproofing under the blind area
Residual penetration of moisture under the blind area is prevented by the main waterproof layer, which is filled with an impermeable geomembrane. It can also be a dense HDPE film, and old banner fabric. It is more convenient to work with rolled materials – they roll out along the bedding and practically do not require joining. When using banner fabric, its seams should have an overlap of 15 cm with bitumen mastic gluing.
The width of the waterproof fabric should be equal to the distance between the wall and the inner edge of the curb stones, plus another 15–20 cm. From the outside, the waterproof film is inserted into the groove between the curb and the backfill, then turns outward. The rest of the gap is tightly clogged with sand.
Then the canvas needs to be thrown onto the bedding, stamped well and tucked the edge onto the base. In this place, it is advisable to make a tight abutment, having smeared the base of the base with a bituminous sealant and fixing the waterproofing with a metal strip and dowels after 50-60 cm. Fastening is performed only last, when the entire canvas is tightly pressed to the base, and all folds and irregularities are smoothed.
Which tile to choose
Typically, the same tiles that were used to lay the yard cover are laid on the blind area. But not all types of paving stones are optimal for the blind area..
It is advisable to avoid highly embossed paving stones and tiles of complex shapes with a large number of thick joints, uneven edges and rounded corners. Flat stones 40-50 mm thick with right angles are ideal. It is recommended to use medium-sized tiles: 12-15 pcs / m2, chamfer is welcomed. It is very good if the tiles are purchased even before excavation – this way you can correctly calculate the indentation when installing curbs and avoid unnecessary undercuts.
The paving slabs with a “glossy” surface without texture are characterized by the greatest durability. On the blind area, the coating dries out slowly and is more exposed to frost erosion, so water absorption should be minimal.
Tile installation should be planned for dry and clear weather. A 2-3 cm layer of finishing leveling is poured over the waterproofing. For him, a dry mixture of sand and cement grade 400 is prepared in advance in a ratio of 5: 1. The layer must be well compacted and leveled with the rule, because the tile will fit exclusively “in a set” without additional mechanical impact. As you install from the dry mix, you will need to prepare small portions of cement mortar, so prepare the finishing bed with a small margin.
First of all, a number of drainage trays are laid out immediately under the curb stones. It is recommended to fill the joint between them with a wet cement mortar. The edge of the tray, located on the inside of the blind area, aligns with the lacing to the level of the main cover.
Next, the starting row of tiles from the base is laid out. The wall may have irregularities, so the installation is carried out along a cord, the position of which is calculated according to the size and number of stones, taking into account 2 mm seams. When installing the starter row, it is necessary to fill the space between the stones and the basement with cement mortar.
The filling of the middle part of the blind area is very fast. For alignment, use a rule or a flat bar that rests on the starter row and tray. When laying the next stone, apply a small amount of wet mortar to its lower edges, then adjust and seat with weak blows of a rubber mallet.
When the coating is laid, it remains only to thoroughly sweep the seams with a mixture of sand and cement 3: 1 and pour over the blind area from a hose, simultaneously washing away the remains of cement dust. On the adjacent soil, you need to dig under the curb to the depth of the liners, then fill the groove with gravel. After the blind area has dried, the remnants of the protruding gate of the waterproofing are cut off with a mounting knife flush with the coating.