Good afternoon, dear guests and subscribers of the "Build for Myself" channel!
By coincidence, I built two houses in my life. The first house was built in 2009, one-storey, with a total area of 90 sq.m., was sold because the family increased by 2 people. The second house was built in 2019, a mansard house, with a total area of 130 sq.m., my channel is dedicated to the construction of this house.
But the article is not about that. On this page I would like to describe the economy and convenience of this or that option and try from personal experience to convey to the reader the practicality of each of the two compared houses.
In order not to overload the article, I do not go deep in particular and for the calculation I use publicly available materials: concrete, brick, metal tiles, etc.
For comparison, I take two houses with the same useful area. For a one-storey house 12x12, the useful area is 119 sq.m. (we throw out the area of external walls 50 cm thick.) For an attic or two-story house 9x9, the usable area of one floor is 59 meters, respectively 2 floors (59 + 59 = 118 sq.m.). In this version, I removed the area onto which the stairs are projected. The staircase takes 5 sq.m. from each floor.
Ultimately, we have two houses with practically the same area of 119 and 118 sq.m., but with different storeys. Let's find out which of the options is more convenient and practical, and which is more economical in construction.
The main criteria for assessing cost savings will be: foundation, walls, stairs, floor and roof. Criteria for convenience and practicality: number of storeys and building area. So...
1. Foundation
Despite the fact that the load from the walls of a one-story house on the ground is much less than from a two-story house due to the lower weight of a running meter of the wall, in in any case, the foundation should be laid below the freezing mark or measures should be taken to insulate the soil in order to prevent its frosty heaving. The construction of a running meter of the foundation in both cases will be identical (I am considering soil with good bearing capacity (2-3 kg / sq. Cm.).
The calculation was carried out using the example of a strip foundation, but using any other type is approximately similar to the difference in% ratio. In this way:
Foundation for 1 floor. houses: 12 * 4 (perimeter) * 1.6 (depth + base) * 0.5 (thickness) = 38.4 cubic meters
For 2nd floor. houses: 9 * 4 * 1.6 * 0.5 = 28.8 cubic meters
If you take a cube of concrete for 3500 rubles. and the same amount for work, then the benefit from a two-story house will be: RUB 67,200 (25% in winnings)
In addition to the volume of concrete, it is necessary to take into account the amount of timber for the formwork, the reinforcement of the structure and the work on excavation. Ultimately, you can save about RUB 90,000
2. Walls
1st floor house: wall area 166 sq.m.
2nd floor house: wall area 218 sq.m., during the construction of the attic, the wall area is 168 sq.m.
If you take an attic house and a one-story house, the costs are identical, in the case of a full-fledged second floor, the difference in material can be from 20 to 40% and this is significant.
Of course, everyone chooses the wall material to taste and performance, but in the example I will take an ordinary brick wall two bricks thick (51 cm), thus:
for a one-story house, the number of bricks: 166 (area) * 0.51 (thickness) * 394 (number of bricks in a cube) = 33 356 pcs.
for a two-story: 218 * 0.51 * 394 = 43 805 pcs.
Let the price of a brick and the work be 15 rubles, then the walls of a one-story house will come out RUB 1,000,680 two-story 1 314 150 rub. (overpayment 314,000 rubles) + cement about 40 bags of 350 rubles each. that's another 14,000, total difference RUB 328,000
3. Ladder and slab
These are some of the most expensive elements of a two-story house. The average cost of a staircase in the final version varies from 100 to 200,000 rubles. taking into account the work, and the design options are much more expensive (in my house the cost of an ordinary staircase was 25,000 rubles for a metal frame. + 71,000 rubles. steps and that's just the material).
As for the floor, since it is a residential floor, completely different requirements are imposed on it than on the attic floor. Overlappings can be on wooden beams, monolith or slabs and the price will range from 120,000 to 250,000 rubles. for the supporting structure. In the case of the attic floor, both options have it.
Yes, for a one-story house, the floor area of the first floor is undoubtedly larger, but still this area does not cover the cost of the floor area of a two-story house. Overlapping is 40-50% more expensive (special work. technology, formwork and many other costs).
So we overpay for the stairs 100-200 tr. and for overlap RUB 65,000 - RUB 125,000. (50% of 130... 250 tr.)
4. Roof
The roofing slopes of a one-story house have at least 1.5 times more area than the slopes of an attic or two-story house. In our version the one-storey house has 194 sq.m. roof, two-storey - 123 sq.m. In addition, the drainage system will be insignificant, but more expensive, since more rainwater needs to be diverted.
As in the case of walls, there are many options for roofing, here there is no friend's taste and color, as a comparison I take the usual option - metal tile.
If you put everything on money, then 194 sq.m. this is 194 * 500 rubles. (tile price per 1 sq.m.) + 194 * 900 rubles. (work) = 271,000 rubles. For 123 sq.m. = 172 200 rubles. The difference is 100,000 rubles.
Do not forget that the scaffolding for the rafter system also requires at least 1.5 times more. Thus, the overpayment for the roof of a one-story house will be 100 - 130 tr. (Percentage is 40-60%.)
Now, I would like to summarize the subtotal of overpayments in the form of a plate that will show at what stage we will overpay, and where we will save:
Undoubtedly, all the numbers are arbitrary, but you can clearly assess which house in its configuration will be the most expensive and cheapest, given the same usable area. Thus, a one-story house will be the most inexpensive, then there is an attic house and a two-story house - the most expensive.
Now, a little about practicality
The one-storey house has a built-up area of 144 sq.m. compared to 81 sq.m., the difference is 63 sq.m., and this is for a minute, more than half a hundred square meters. But, the presence of a ladder can be dangerous for the baby in the family or cause difficulty in climbing for the older generation.
The attic house looks neater and more compact than a full-fledged two-story or stretched one-story, but sloping ceilings interfere and take up the area.
It is also worth noting that heating a one-story house is much cheaper due to the smaller area of the walls bordering the street.
Ultimately, it's up to you to decide. For example, my second house is an attic, but if the size of the site allowed, I would make a one-story one again!
I hope this article was useful to you. Thanks for attention!
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