Best formwork for the foundation

Neither building is not without concrete and where the concrete - and there formwork. Particular attention should be paid formwork used in the manufacture of the foundation. After all, its reliability as a reason for the house depends on many things.

To avoid this and uzant, from which make shuttering cheap, use the practical experience FORUMHOUSE experts.

What do the formwork

formwork quality largely depends on the material from which made it. Formwork for the foundation is made of: laminated plywood, OSB, DSP sheets, flat slate, non-removable sheets of polystyrene foam. The move comes even old furniture, as well as "beushnye" pallets.

But the undisputed leader - plain wood.

How to make a timbering from boards

Gameday advise how to make boards for planking: To assemble the horizontal shields is recommended edged boards size - 100h25 150h30 mm mm, and vertical pepper - to take the bar 100x50 mm, stressing it in shield edge.

Step vertical installation is transverse (50x100 mm bar) - 70 to 100 cm. To give greater rigidity formwork, with each of its sides, horizontally installed two boards 50x100 mm, top and bottom.

With thoughtful konstruktive strength and proper performance data sizes of boards is sufficient to withstand the pressure of the concrete mix at the construction wall.

Choosing boards for this construction, it is necessary to consider directly embodiment further use. Because formwork for the foundation will require more than one cube, board inefficiently used only once. To the board after dismantling the left "merchantable wood", it is necessary to protect them from direct contact with the concrete. To set up the formwork for the foundation, it is necessary to evict her from inside a strong polyethylene film designated stapler. Erection of structures lead to better self-tapping screws. In this case, it can be easily disassembled, reducing to a minimum the damage to the boards.

D.-50 (Member FORUMHOUSE):

I after dismantling the formwork board 30h120 mm to let the crate. Before this cleaned surface of the boards by staples steplernyh. The main thing - to disassemble everything carefully.

UKSUS70 (participant FORUMHOUSE):

I have a roof of the house is made up of 40 board-ki left after dismantling the formwork. Formwork previously closed film, boards, sticking in the corners, not sawed, all assembled on the screws. After dismantling boards were like new!

Advice from Forumhouse, how to assemble the formwork: the tape must be attached to it so as to prevent it turning out or gap during concrete pouring. Think through in advance, the supply of concrete to be produced with a hand. In the course of its movement, it does not have to flow under the overlaps of the film pieces. Otherwise, the film edge tucked can zamonolititsya foundation across the tape, which will reduce its strength characteristics. Also, the film minimizes concrete pouring through the cracks in the boards.

Decking: what to do better

During the construction of the correct construction is first necessary to consider it constructive and all the necessary power elements (spacers, jib, tie). It is one thing: Pouring tape height from the ground to 30-40 cm, and quite another - to fill in the walls of the cellar is 2.5 meters tall. Especially, if the concrete is fed by means of a concrete pump.

SkyRock (participant FORUMHOUSE):

I built a timbering of 25-x boards. Ties did not do, I thought, will stand, because every 30 cm, I put wooden braces. When pouring concrete formwork rasporlo, so much so that twice had to bail mixture poured out, then back to fasten the formwork and concrete is cast by hand back. Taught very bitter experience, I now will definitely pull the wall ties.

There are cases when, without bothering to properly perform the strengthening of the formwork, we find that when pouring or vibration, it just breaks. All the concrete is poured on the ground. The design has to be patched on an emergency basis, resulting in large financial losses. Conclusion: The formwork should be further strengthened.

strengthening of formwork

Many novice developers can not imagine what a huge arching forces act on the formwork during concrete pouring. Referring to the figures.

Igel2126 (participant FORUMHOUSE):

I recently filled the plate height of 25 cm. Decking just lying on the ground, in the corners was attached to the screws, in some places was podporta stones and bricks - nothing anywhere squeezed and did not move. But that is suitable in my case, does not pass at high casting tape foundation.

Such an example. By SNP III-15-76 pressure on the wall = PhH. Hence: 2500h0.25 = 625kgs / sq.m. If the meter casing 1 has an area 0.25h1 = 0.25 m, the pressure at 1 meter will 625h0,25 = 156 kg / MP., Taking into account the vibration concrete 200kgs / MP.

Formwork for the foundation with his own hands.

If the height of the shield is equal to 0.9 m and unloading of concrete made from a concrete pump, then, on the same SNIP, the pressure will be 2500h0.9 + 400 = 2650 kg / m2. Hence: the pressure on the 1 meter will be 2385 kg / MP. The difference is huge!

on the wall formwork pressure is directly proportional to the stake of concrete and has a maximum value at the bottom.

But it so happens that the formwork even properly strapped with metal studs, "it gives a leak." And it does not stand a threaded stud element. Thread or crushes or "shoots" a nut. Why it happens? When the contraction industrial formwork used special pins, bolts and reinforced with an enlarged diameter washer.

In the private house-building used conventional threaded bolts - M8 / M10 / M12 and nuts, bought at the nearest building market. Pin Class 8.8, 10 mm in diameter, in guests are required to withstand a load of 6.7 tonnes, but in a normal sale, mainly goes with studs "sunken" diameter and shape of the thread is not in accordance with GOST. metal quality too low, in the best case, such a stud will withstand a load of 1.5 tonnes.

Alexey-Snezhuchastnik (FORUMHOUSE):

I bought for the foundation studs to the M8. I wanted to see what the actual load they sustain. I tried them on a tensile testing machine. Result: the audio stranded nut, with a load of about 100 kg was shearing (crushing), the thread studs. When the two nuts stranded hairpin sustained load (stripped threads, but the hairpin remains intact) has 500 kg.

Conclusion: to stud "worked", it is necessary on each of its sides two nuts screwed on. Or use special nuts increased length.

However, this does not guarantee that the hairpin "turns to the work" by 100%. It is necessary to arrange the studs so that they give the maximum effect.

DeDmitry (participant FORUMHOUSE):

I "drove" two variants of arrangements of studs in the formwork in a special program. And there you are: take the wooden vertical rack 50x100 mm. We put it to the panel edge, the height of 2.3 meters. Asking load - 10 kN \ m (4 kN - the vibrator, 6kN - concrete pressure of a column of 2.3 meters). Contractible formwork three pins, with a distance of 70 cm. The first hairpin from the bottom - at the height of 50 cm. We obtain the picture deflection and stress in the beam.

The screenshot shows that most deviates a lower end of the beam (5 mm). Those. the likelihood is high that the retaining beam breaks here. Parting studs differently. Lower now lies at a height of 30 cm.

Now the load is distributed differently. The maximum voltage is reduced by almost 3 times (5.4), and the deflection is reduced by 10 times.

Costeapechnik (participant FORUMHOUSE):

My advice - if you're going to pull the formwork pins, they should be placed between two vertical bars (distance equal to the diameter of the stud between them). But finding quality studs and nuts are difficult, and they are expensive. Where then do with all this metal? If only for the installation of roof system.

Advice from FORUMHOUSE: that after pouring strip foundation from it could easily pull out pin, it is placed in a pre-IPA small diameter tube or electrical polypropylene tube. Holes in the base after removing studs embedded cement-sand mixture.

To reduce the small threaded stud portion of expenses can be welded to the reinforcement required length. And on the opposite end of the weld on the jumper, to get the letter T.

Much easier and cheaper - to make the strengthening of the formwork frame "pigtail" of binding wire diameter of 1.2 mm and laced it out 6-7 threads. Such coupling stronger than the "pigtail", of woven wire 2 mm in diameter 3 filaments.

"Pigtail" is pushed in the gap between the shuttering boards or in a pre-drilled hole. It pulls together two vertical support beam structure. To formwork wall by twisting "pigtails" is not deformed, inside formwork is laid rebar limiter diameter of 10-12 mm.

Special attention should formwork under the ground floor.

Gameday recommend: at the height of the walls more than 2 meters should be broken into two stages fill and pour at a time no more than 1-1.2 meters. Then rearrange the formwork above. Besides the fact that this makeshift removable formwork cheaper (Materials) than mounted directly on the entire height, the risk that it will withstand loads during concrete pouring is significantly reduced.

And, to fill a number of concrete and vibrating it must be layers of 50 cm thick, round and round until it is filled with the required height of the foundation. This will avoid unnecessary load at one point the formwork because pouring height is increased gradually. And by the time the lower concrete layer has a predetermined height grab, which accordingly reduce the pressure on the formwork wall.

And finally, a few tips from members of the forum on the concrete acceptance:

• Concrete pouring of the foundation must be ordered with a small margin - about 1m3 plus. If part of the concrete "escape" when pouring concrete on site or "nedolyut" solution to remain in reserve.

• Pre-determined location where it will be possible to drain the excess concrete. This can be an access road.
• Concrete pumps for the desired landing approximately 6x8 meters.
• Before pouring the concrete need to prepare in advance the repair kit. Props, poles, planks, a hammer, nails, hammer, bucket, container, where it is possible to temporarily drain spilled concrete, spare wooden shield. If the formwork "explode" when pouring, then run on the site and look for than to close up the gap, will not have time.

• When pouring the foundation concrete pump should immediately agree on a concrete site to concrete mixers were one after the other without interruption. This avoids downtime and, as a consequence, an additional fee for the lease expensive equipment.
• At acceptance of concrete necessarily Wear protective goggles and disposable medical gloves on his hands. Concrete in contact with an open skin can cause chemical burns.
• Required hat and tight clothing. Moreover, clothing is chosen such that then will not throw a pity.

Pour foundation "in the ground" it is possible, if we use the advice forumchanin. After reading this topic, you will understand, how to make the formwork. You can also see the results of the dispute: "Does it even need a wooden formwork"? Additionally, watch the video with a master class by FORUMHOUSE, by assembling reusable formwork.

Discuss the article and read other materials devoted to country life you can on the websiteFORUMHOUSE.

Subscribe to the channel so as not to miss the next release!