Spray foam underfloor insulation

[dazzler9000]

Hi all,
I've recently come to the conclusion, that my inherited wet underfloor heating is more than likely sat on cement boards, then floorboards which face the outdoor open suspended floor cavity. I still need to find a section to investigate and confirm, but I have a hunch that there is no insulation under the floor and a fair amount of the heat is heating up the underside of my house.

I had a plan to lift all of the ground floor coverings (tile and engineered oak flooring) and install Celotex. You can imagine, this is an unpopular option with the other half. I then stumbled across this - https://q-bot.co/ it looks great and could be an easy option.

Has anyone any experience with installing underfloor foam insulation? Probably wise to get a quote for a q-bot install and a human install.

 

[tell80]

Its difficult to understand your post: is the UFH protected? is it in a screed?

Whatever, my opinion is to stay far away from foam in any of its applications - it never seems to do whats promised on the label, & unforseen problems often crop up later.

 

[jacko555]

While the septics seem to successfully use it, the UK doesn't like it.

https://commonslibrary.parliament.uk/spray-foam-insulation-and-mortgages/

(RICS) has warned that a surveyor may “reduce the value of the property” if they encounter spray foam insulation during an inspection. The RICS said this may “even render a property un-mortgageable in the eyes of a lender”.

 

[dazzler9000]

Its difficult to understand your post: is the UFH protected? is it in a screed?

Whatever, my opinion is to stay far away from foam in any of its applications - it never seems to do whats promised on the label, & unforseen problems often crop up later.

I'm unsure as it's under a tiled and oak floor that I don't want to pull up to investigate. All I know is the house is freezing and doesn't retain heat and I know from looking under the stairs and lifting some floorboards, there is just a hole under the house. I can't be sure whether they insulated where the UFH starts, but I have suspicions that they didn't.

I will have a better look down the hole again when it's a bit warmer and see if I can crawl under and investigate .

I was hoping spray foam was my answer. Seems to get good reviews.

 

[dazzler9000]

While the septics seem to successfully use it, the UK doesn't like it.

https://commonslibrary.parliament.uk/spray-foam-insulation-and-mortgages/

I understand the issues in the loft. I know it's not very popular due to condensation and rotting timber, but I would have thought under the house would be okay, especially if air bricks were still aren't blocked and ventilation isn't an issue.

 

[Mr Chibs]

You need to get under the floor (if possible) or lift a board and have a look what you have, before deciding what to/not do.

Spray foam is not the preferred option for insulating, due to increased ventilation/condensation issues if not properly applied.

 

[tell80]

Post #3,
who are the septics?

 

[dazzler9000]

You need to get under the floor (if possible) or lift a board and have a look what you have, before deciding what to/not do.

Spray foam is not the preferred option for insulating, due to increased ventilation/condensation issues if not properly applied.

Yep, as soon as I get a chance, I will investigate.

 

[Why Not Indeed]

Post #3,
who are the septics?

"Septic tanks" = yanks = Americans.

 

[tell80]

Why Not Indeed,
Thanks for that.

What did post # 3 mean?
With reference to heating: America has very little UFH the US is mainly the land of AC.
With ref to foam: the US construction industry & OSHA have long been in dispute about using it.
Its sometimes been a deal breaker for house sales.

 

[Why Not Indeed]

With reference to heating: America has very little UFH the US is mainly the land of AC.

The climate in the US covers everything from sub-tropical to arctic. So there's probably somewhere in the US that has a similar climate to the UK.
Even if the OP could get spray foam installed properly, how would you ever convince the next buyer? They would probably run a mile.
I agree that spray foam under a suspended timber floor seems like a lower risk of trapping moisture with nowhere for it to go, than an under-roof installation. But I'm not an expert so don't take my word for it.

 

[dazzler9000]

Bit of an update today. I lifted a couple of the floorboards under my stairs. From what I can tell from the visibility I had, there is no foam/PIR boards under the floor between the 100mm joists. I got a couple of photos from above and it looks like the hot feed from the boiler to the UFH manifold is just dangling in the floor cavity uninsulated. I'm assuming this isn't best practice or standard insulation?

I removed some wood trim between my tiled/wooded floor to try and gauge what was under there and there appears to be some plastic with polystyrene balls. I didn't want to poke or split it, but it looked wafer-thin. What a mess! I'm tempted to rip it all up one day, insulate between the joists and install rads everywhere.

A friend of mine also commented that the underfloor heating pipe looked a little slim. I measured it and it's just over 12mm. Is this standard?
Looking at the pic below, the pipes appear to be spaced about 15cm apart also.

 

[Mr Chibs]

Without wishing to add more misery, 15mm is standard pipe, as far as I'm aware.

The insulation I'm presuming is underlay for the wood floor, and will be a few mm thick, this will do nothing but leach heat out.

Others will comment with suggestions, but I'd address the insulation situation, doesn't look like a lot of room to get under there.

 

[foxhole]

It’s a manifold system which allows smaller diameters pipes to aid installation .
Your timbers need ventilation whether it be loft or flooring .

 

[dazzler9000]

Thanks everyone, one thing's for sure. This place is an absolute disaster.

So, guess I'm back to having to rip out the floor at some point, insulating with PIR board and starting again. If only people could do things properly first time.