As seen in the picture, the floor joists are positioned so that each glued laminated beam is as short as possible - of course.
On top of this, a waterborne underfloor heating system is to be installed, Uponor 20x2mm.
The idea was to choose Uponor's option, which involves fastening battens 28x120mm over AND across the glulam beams. With this dimension, one can avoid laying a tongue and groove chipboard on top, which is necessary if instead using 22x120mm battens. Great, one less heat-consuming layer (the chipboard), and thus 22 mm closer to the heat source.
Now to my problems:
The parquet floor is to be laid ACROSS the 28x120mm battens according to Uponor's recommendations. Great, this means in my case that the floor will be laid in the wrong direction. As everyone surely knows, floors should be laid ALONG the largest windows - YES, our largest windows are on the left short wall, which is also south-facing = a lot of sunlight. Furthermore, floors should always be laid ALONG the longest wall. We want to lay it along according to the last two recommendations.
Questions:
1. Is it so crucial with Uponor's recommendation that says ACROSS the 28x120mm battens? I assume it is to prevent the longitudinal tongue of the parquet floor from ending up precisely between two battens and thereby stressing the parquet's tongue. But there's the underfloor heating pipe in its heat distribution plate, so it should be fine?
2. It seems reasonably impossible to get hold of the 28x120mm dimension. I saw that some use the much more common 28x70mm, but if you use this dimension, don't you lose some rigidity in the floor due to weaker width per batten compared to a 120mm wide?
3. Should one use felt paper between the underfloor heating plates and the parquet floor?
4. I would prefer not to turn 90 degrees with an extra layer of planks on top or between each glulam beam, then lay the 28x120mm battens on top, now in the "correct" direction for the parquet floor. I want to lay 28x70 across the glulam beams as in the picture, push in the heat distribution plates in between, insert the 20x2 pipe, cover with felt paper, and then the parquet floor ALONG the 28x120mm battens, and thereby the floor would be in the correct direction concerning sunlight, etc., unless someone strongly objects?
Is there no possibility to brace in the joists and lay your 28x70 in the "right" direction for you? And as I've learned about floor laying, the floor should be laid along with the light entry. And then it matches the longest wall.
I see the following advantages:
-solves my problem of "turning" 90 degrees to get the right orientation for the parquet
-no need for felt paper
-improves sound insulation
-plaster conducts heat better than wood
-dead material is always good
A challenging question:
Can't renovation plasterboard be used instead, 6mm thick?
Both renovation plasterboard and floor plasterboard are fiber-reinforced
Asking because it would mean half the weight and a bit cheaper
Working on laying the same system.
1. If you want the parquet stable, it should be laid across and be at least 15mm. If I understand you correctly, points 1 & 4 are connected since you want the right direction considering the light. We have the same dilemma but solved it by laying Dutch patterned parquet.
2. I got hold of 28x120 by contacting a smaller lumberyard that is part of the XL-Bygg chain, they provided untreated timber intended for decking (however, it cost more than treated timber...)
3. Whether to use liner paper or not depends on what the floor manufacturer says.
4. Point 2?
