ᐅ Concrete slab with strip foundation and frost protection apron
Created on: 8 Feb 2019 21:48
C
Christian K.
Hello friends of house building,
Until now, I always assumed that you insulate a slab foundation using formwork. Simply placing a shell of XPS insulation and then pouring the slab. Of course, that’s a very simplified explanation.
Our construction manager now suggests a frost skirt. This means that the masonry and the slab will be insulated with x cm of insulation material, and the strip footing will receive 5 cm (2 inches) of insulation. The area below the slab will not be insulated because the strip footing with the frost skirt makes it unnecessary, AND insulation of walls, roof, etc., provides more benefit than insulating the slab. It could be insulated, but it would add more cost.
What do you think? We do need to keep an eye on costs, and if it is more than just a nice-to-have, we have no problem with it, but I must admit that we have little information (and no experience at all) on this.
So long...
Until now, I always assumed that you insulate a slab foundation using formwork. Simply placing a shell of XPS insulation and then pouring the slab. Of course, that’s a very simplified explanation.
Our construction manager now suggests a frost skirt. This means that the masonry and the slab will be insulated with x cm of insulation material, and the strip footing will receive 5 cm (2 inches) of insulation. The area below the slab will not be insulated because the strip footing with the frost skirt makes it unnecessary, AND insulation of walls, roof, etc., provides more benefit than insulating the slab. It could be insulated, but it would add more cost.
What do you think? We do need to keep an eye on costs, and if it is more than just a nice-to-have, we have no problem with it, but I must admit that we have little information (and no experience at all) on this.
So long...
The ground slab is still insulated from the outside if an external thermal insulation composite system (ETICS) is used... otherwise, hardly any site management companies do anything under the ground slab and strip foundations except lay a membrane.
Of course, this only applies if nothing else is requested or paid for and if the construction is carried out according to "standard" practice.
Of course, this only applies if nothing else is requested or paid for and if the construction is carried out according to "standard" practice.
In my case (with a basement), there is no concrete element in contact with the ground or air (neither from below, above, nor on the sides) that did not have to be insulated with 12cm XPS (5 inches). The energy consultant was really meticulous.
I would be very interested to see how the comparison (energy loss / heating demand) would look without insulation.
I would be very interested to see how the comparison (energy loss / heating demand) would look without insulation.
Learned something new again, thanks!
What do general contractors usually charge for insulating the foundation slab that leads to it often being skipped? We poured a new slab (around 35m² (377 ft²)) ourselves in an existing building and insulated it continuously with 5cm (2 inches) around the edges and 10cm (4 inches) beneath; it didn’t cost even 400€.
What do general contractors usually charge for insulating the foundation slab that leads to it often being skipped? We poured a new slab (around 35m² (377 ft²)) ourselves in an existing building and insulated it continuously with 5cm (2 inches) around the edges and 10cm (4 inches) beneath; it didn’t cost even 400€.
Dr Hix schrieb:
Learned something new, thanks!
What does a general contractor typically charge for insulating the floor slab that it’s often skipped? We partially poured a new slab (about 35m² (380 sq ft)) ourselves in an existing building and insulated it continuously with 5cm (2 inches) around and 10cm (4 inches) underneath; it didn’t cost more than €400. Our shell construction contractor wanted €22.30 net per square meter (including materials and labor) for 12cm (5 inches) XPS insulation.
But those prices are already from late 2017/early 2018.
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