Amadeo II 1st floor slab and installation of AVI Thermokorb

28 February 2010 - Comments (1)

Construction

This year winter was particularly harsh in Belgrade and we, like many others, had to stop the construction for a month. With the good days back, we were able to finish the 1st floor slab of Amadeo II. This floor had 2 balconies which had to be treated not to have thermal bridges. This time we used AVI Thermokorb, a load bearing thermal break from Austria.

All floor slabs above the ground floor are standard precast floor slabs with ceiling bricks and precast beams. The 2 specificities on Amadeo II is the fact that we insulate the outer edges of the slab, and that we take care of fixing thermal bridges created by the balconies.

Precast floor slab with ceiling bricks and precast beams on Amadeo II.

First floor slab of Amadeo II before to pour concrete.

Insulation of the outer edges of the slab

Because we build with a monolithic wall system, for which no additional external thermal insulation will be put, we must insure that all concrete parts are insulated at least from the outer side. That is especially true for the slab which is made of concrete.

Detail of the outer edge insulation of the slab with Tarolit 5cm.

For the insulation we use Tarolit 5cm. It is expanded polystyrene coated with wood particles which makes it very sturdy.

Treating thermal bridges on balconies

Plain cantilever balconies create large thermal bridges, as the concrete slab continues on the outer side to form the balcony. The balcony becomes a big radiator dissipating the inside heat outside. This has to be fixed. For cantilever balconies, the elegant way to fix that is to place a thermal break in the slab that prevents inside heat to flow onto the balcony.

Installing AVI Thermokorb on a balcony of Amadeo II.

Of course, that thermal break must allow the balcony to still be supported. That kind of load bearing thermal break has to be very well engineered and sized to fulfill both functions: thermal break and load bearing element. This time around we used AVI Thermokorb for the job.

AVI Thermokorb installed on a balcony of Amadeo II.

AVI Thermokorb come in several sizes depending on the thickness of the balcony slab and with different reinforcement depending of the weight to be supported and the geometry of the balcony. It is a very sturdy element made of dense polystyrene as the thermal break and of iron reinforcement soldered on a steal core.

AVI Thermokorb close-up. We can see the steel core on which the iron reinforcement is soldered.

A thin additional layer of extruded polystyrene was used to thicken the thermal break of Thermokorb and match the thickness of the slab.

The 2 complete balconies with AVI Thermokorb.

An important rule to respect, when using that type of thermal break on a cantilever balcony, is to leave an equivalent concrete field in front of the balcony as the balcony itself. On a slab done with precast elements, that means leaving a space that will be filled with concrete in front of the balcony. That is to counterbalance the forces of the balcony transmitted by the reinforcement by an equivalent weight.

Pouring concrete

For pouring concrete, Marmil Inženjering did some great acrobatics with their concrete pump

Marmil Inženjering concrete pump up in the air.

Pouring concrete on Amadeo II 1st floor slab.

The finished slab on the next day.

Zoom on the balconies once finished.