I am building a rear extension and have hit an issue with underfloor heating. The sub-floor here is half a floating floor (joists and OSB) and half concrete screed.
The builders built the screed floor, citing regulations or misunderstanding the building inspector. According to my approved plans only the ¼ of the floor area that is new should, in fact, have a screed floor.
However, before they put it in I thought this was an opportunity for wet underfloor central heating. They have laid this in a 50mm screed, with pipes at a depth of about 2.5 cms. The pipes under the OSB are laid on Kingspan insulation and are flush with the boards.
After two weeks they put on the underfloor heating with a water temperature of approx 45c.
There are cracks in the screed. Perhaps there would be anyway with a screed this thin. I attach pictures showing it breaking up. The main part of the screed has no cracks as yet, however.
The builders have no expertise in underfloor heating and cannot appreciate why I am reluctant to lay an expensive wood floor on to of this sub-floor.
The underfloor heating in this room is in addition to a wood burner. There will also be a radiator in a new room to the rear, which will help. It is also very well insulated. The requirements of the underfloor heating would not be great.
My question is whether this floor is worth preserving with. If so, I would for the time being loose lay old floorboards on top as the hardiest and most expendable floor covering. I would secure them permanently in two months time.
Alternatively, if this floor is useless and the screed will simply break cutting the UFH pipes, then I could have them dig it out now, replace most of it with a joist and timber floating floor and fit radiators.
This would be backward step and likely to be contested by the builders.
Any views about this floor greatly appreciated. I (hopefully) attach pictures.
![GALLERY]](http://[GALLERY=media, 28582][/GALLERY])
![GALLERY]](http://[GALLERY=media, 28583][/GALLERY])
![GALLERY]](http://[GALLERY=media, 28584][/GALLERY])
![GALLERY]](http://[GALLERY=media, 28585][/GALLERY])
The builders built the screed floor, citing regulations or misunderstanding the building inspector. According to my approved plans only the ¼ of the floor area that is new should, in fact, have a screed floor.
However, before they put it in I thought this was an opportunity for wet underfloor central heating. They have laid this in a 50mm screed, with pipes at a depth of about 2.5 cms. The pipes under the OSB are laid on Kingspan insulation and are flush with the boards.
After two weeks they put on the underfloor heating with a water temperature of approx 45c.
There are cracks in the screed. Perhaps there would be anyway with a screed this thin. I attach pictures showing it breaking up. The main part of the screed has no cracks as yet, however.
The builders have no expertise in underfloor heating and cannot appreciate why I am reluctant to lay an expensive wood floor on to of this sub-floor.
The underfloor heating in this room is in addition to a wood burner. There will also be a radiator in a new room to the rear, which will help. It is also very well insulated. The requirements of the underfloor heating would not be great.
My question is whether this floor is worth preserving with. If so, I would for the time being loose lay old floorboards on top as the hardiest and most expendable floor covering. I would secure them permanently in two months time.
Alternatively, if this floor is useless and the screed will simply break cutting the UFH pipes, then I could have them dig it out now, replace most of it with a joist and timber floating floor and fit radiators.
This would be backward step and likely to be contested by the builders.
Any views about this floor greatly appreciated. I (hopefully) attach pictures.
