Flat roof house projects: advantages and disadvantages, features, lightweight roof construction and hard roof construction

Modern projects of houses with a flat roof are quite rare (after all, pitched roofs are more common in our country), but still they occupy a certain share in private construction.

Moreover, with the advent of modern roofing materials and technologies that allow for reliable waterproofing of the roof, houses with flat roofs began to increase in popularity.

That is why, probably, a house with a flat roof today is considered rather as an exclusive construction, which stands out against the background of fairly similar hipped and pitched roofs.

In this article, we will consider the main aspects of the design and construction of a flat roof, as well as the benefits that provide the owner of the house and cottages with a flat roof.

Flat roof - advantages and disadvantages

Benefits of a flat roof

When developing a flat roof house project, we inevitably ask ourselves the question - what are its main advantages?

The benefits that you get by equipping a flat roof include:

1. Creative design. As we mentioned in the introductory part of this article, a flat roof house looks exclusive and unusual.
   Moreover, by equipping a flat roof, you definitely make a choice in favor of modern European design trends, which is also important.
2. In addition to design, projects of houses and cottages with a flat roof also imply the presence of quite tangible material benefits..
   Such benefits include, for example, the possibility of arranging an exploited roof. From a purely practical point of view, you get a flat area sufficient for arranging a recreation area with a lawn or a platform with a mini-pool (of course, if the supporting structures allow it).
   In any case, a flat roof is an additional area that can be used.

   

3. Another benefit of the practical plan is the greater economic benefit of building a flat roof..
   As a rule, cottage projects with a flat roof are less expensive in terms of design costs.
4. The following advantage is rather controversial, but it should still be mentioned. The thing is that snow accumulates on a flat roof in winter, which in itself is a good heat insulator.
   Thus, a cottage with a flat roof in some cases may require less heat for heating. However, the ability flat roofs keeping snow is a double-edged sword, and the problems caused by excessive accumulation of precipitation on a flat roof will be discussed below.

Disadvantages of a flat roof

Like any constructive solution, flat roof house designs are not without drawbacks:

• Flat roof installation must be completed in compliance with all requirements for waterproofing.
  The slightest deviation in technology, negligence or simple negligence - and now we already have a leaking roof on which water accumulates.
  Repair of such a roof can cost a very serious amount - and in the worst case, it will require a complete reconstruction.

• As we mentioned earlier, a flat roof, unlike a pitched one, contributes to the accumulation of snow..
  Moreover, if you want to continue to operate the roof in the winter, you will have to clean it, moreover, manually. And as soon as the snow begins to melt, the waterproofing of the roof will experience a serious load.

Arrangement of a flat roof

Features of flat roofs

When developing projects for one-story houses with a flat roof (and indeed any back with a flat roof), you need to remember the following:

• A flat roof is flat in name only.. In fact, when designing a flat roof, a slope angle of 5 to 15 degrees must be laid in it, otherwise the roof will turn into a kind of “trough” for collecting rain and melt water.

• If the roof of your house is perfectly flat, then you need to carry out the so-called ramping - a set of measures to give the roof a slope sufficient for drainage.
  For leveling, either fixed-angle polymer sheets (polystyrene boards) or bulk materials with a concrete screed are used.

  

Note! It is possible to refuse the slope, however, in this case, even at the stage of designing the roof, it is necessary to set the angle at which the bearing plane of the roof will be laid.

Projects of private houses with a flat roof provide for the arrangement of two types of flat roofs:

• Lightweight flat roofs
• Exploited flat roofs

It is about the features of the arrangement of roofs of these two types that we will describe further:

Construction of a lightweight flat roof

A lightweight flat roof (i.e. one that does not provide for operation) is erected according to the following algorithm:

• We lay the main beams directly on the load-bearing walls or on the Mauerlat fixed on them. As the main beams, we use wooden beams with a section of 100x100 or 150x200 mm (depending on the estimated weight of the roof). We lay the beams in increments of 0.5-1m and fix them to the base with anchor studs.

  

• On top of the beams, we mount a solid-type lathing from an edged board with a thickness of about an inch or OSB-boards of comparable strength. crate must not contain slots or holes.
• We lay a waterproofing membrane on top of the crate. We lay the waterproofing in several layers, carefully gluing the joints between the sheets of material using construction tape or special glue

Note! It is not worth saving at this stage and using relatively cheap roofing material instead of membrane waterproofing. Savings on waterproofing when arranging a flat roof often "goes sideways."

• The next step is the arrangement of thermal insulation. Extruded polystyrene foam, mineral wool or similar materials can be used as thermal insulation material. We lay the insulation on top of the waterproofing without gaps, since even the slightest leak can become a “cold bridge”.
• At the same stage, we equip the ventilation vents - they will prevent the accumulation of condensate and waterlogging of the insulation.
• Expanded clay can also be used as a heater: very often this type of insulation is laid in the project of a one-story house with a flat roof. In this case, the expanded clay layer must be at least 100 mm.
• The final stage of the roof arrangement is the waterproofing protection of the roof. For this, special roofing membranes are used, which are widely available on the modern window market.

The light-weight flat roof that you get in the end does an excellent job with its direct duties. However, it cannot withstand a more or less serious load, and therefore it will not be possible to operate it. If you want to equip a small recreation area on the roof, the roof construction technology will be different.

Construction of a flat roof with a solid roof

The project of a cottage with a flat roof and a hard roof implies that the resulting roof will not sag under load. Naturally, to achieve such a result, it is necessary to make some efforts. There are several ways to arrange a solid roof:

• The easiest is to lay concrete slabs as a floor. Naturally, load-bearing structures must have an appropriate margin of safety, and heavy equipment will have to be involved. At the same time, the roof of the slabs requires insulation - and it will be possible to equip it only from the inside of the room.

 

• The second method is the manufacture of roofing on the basis of metal support beams. As a support for the roof, T-beams or I-beams, as well as channel bars (No. 14 - 16), are used. On top of the beams we lay a plank flooring from a board with a minimum thickness of 22 mm. A layer of expanded clay with a minimum thickness of 150 mm is poured over the flooring. The concrete screed laid on top forms a hard surface.

 

• However, the most modern is the technology of arranging a solid roof using ceramic roofing blocks. Such blocks are laid directly on the support beams and, due to their properties, provide the roof with not only mechanical strength, but also good heat and sound insulation characteristics. Also among the advantages of ceramic roofing blocks can be mentioned their absolute resistance to moisture. The screed on such a roof is poured without prior backfilling of expanded clay.

The only drawback of such blocks is their high cost.

It is also possible to lay a roofing membrane on the roof of a house with a flat roof of a hard type. It will not only not worsen the operational properties of the roof, but will also provide the necessary level of waterproofing.

Whichever project we choose, it is important to remember that flat roofs are very sensitive to the quality of waterproofing, and if a pitched roof, due to its design, is able to hide some flaws in work, then on a flat roof water will always find its way into the room.

Therefore, if you are thinking about building a house with a flat roof, the projects of each section of the roof must be developed and implemented very carefully. But in the end you get a really outstanding result!

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