Guidance on underfloor heating in a 1950 bungalow

[swank]

Context - we recently purchased a 4 bedroom Bungalow with a top and rear extension. It is a 1940-1950 build with suspended timber flooring and solid walls. The rear extension kitchen was done in the last five years and is concrete flooring. The upstairs is also done in the last five year , so has cavity stud walls and better insulation. All windows are double glazed. 

We are looking to renovate our ground floor and one thing we want to do is get underfloor heating. Our builder recommended that we can either go for spreader plate system or a pregrooved insulation board of 25mm

I was hoping to get everyone's guidance with the following:

1. Will the levels of floor insulations you would expect from a 1950 house, is it a good idea to go with underfloor heating with the above mentioned systems? Because if we have to redo the entire flooring to upgrade insulation, it would become quite expensive 

2. I talked to one of the build regs inspector. They mentioned that the highest specification of regs are very high specification, but realistically they dont expect it can be always done during renovating, so they are flexible on what can be done. So I am hoping building regs wont be an issue, any thoughts

3. Is any one of the above systems better than other ? Are they situations when one is better than the other

4. Any thing we can do with flooring insulation which could be a quick win without massively increasing the height or cause redoing the sub floor

Thank you for your guidance. 

[JohnMo]

With UFH you need lots of insulation, aiming for a floor U value of 0.15 (150mm PUR, or 250mm of good mineral wool) or better or frankly don't waste your hard earned money installing and then for ever more, paying for heating.

 

 

[swank]

7 hours ago, JohnMo said:

With UFH you need lots of insulation, aiming for a floor U value of 0.15 (150mm PUR, or 250mm of good mineral wool) or better or frankly don't waste your hard earned money installing and then for ever more, paying for heating.

 

 

Thank you this is helpful. Do you have any recommendations on what is the best way to do it in an old house with suspended timber flooring. Raising the floor height will be quite challenging for us, is there a way to do with the existing floor height in a less disruptive/expensive way?

[JohnMo]

There have been a couple of similar threads recently, with links on how to do suspended floor insulation. Sorry can't be much more help. Take a scan through relevent sections of the forum.

[swank]

11 hours ago, JohnMo said:

There have been a couple of similar threads recently, with links on how to do suspended floor insulation. Sorry can't be much more help. Take a scan through relevent sections of the forum.

Sure thank you .

[oranjeboom]

I also started with a 1950's bungalow and was adamant that I could insulate with some of the available spreader boards on the market where some manufacturers sail very close to the wind with regards to having 'sufficient insulation levels' on their product. I was almost tempted, but after doing research, I just had to face reality to either stump up the money for decent insulation and work or to pay stupid bills on heating. I went with ripping up the concrete base and dug up 400mm and filled it with insulation (PIR/EPS) with a new UFH embedded into the concrete. Had some issues on the way

 

 

But glad I went that way.

 

If you only have timber, what void do you have underneath? You may not have to dig up to much to get better than BuildStd insulation levels in there.

 

 

[Jilly]

Have you looked at Kingspan Kooltherm K03?

[Roger440]

Late to this, but at that age, it definitely shouldnt have solid walls. There must be a cavity?

[HughF]

Rip out timber floors, dig down, hardcore, 200 pir, 125mm conc…

 

Dont waste your time with overlay systems.