Are these spreader plates salvageable?

[ADringer]

Hi,

 

I've got spreader plates currently being installed, and at first they were installed incorrectly. The insulation was installed too low and so the plates bent from the joist down to the boards rather than being flat. They were also installed overlapping.

 

This is now being rectified, however I'm a little concerned about the uniformity of the plates. If they were installed properly initially then the plates would be completely flat, however as they have been bent previously I'm concerned there might not be full contact between the plate and subfloor and so be less efficient.

 

I've attached photos of the plates. It still needs to be redone (boards need to be brought up a little) but are the plates ok to use if installed correctly or should I just scrap them and get replacements to ensure uniformity?

 

Thanks!

[markc]

You will never get full contact between the plate and subfloor, and the plates are there to distribute the heat overs wider area. Bends are easily flattened out and you never see them after fitting so creases and bends are not a problem

[Nickfromwales]

If there’s no access from below, eg to staple the plates to the underside of the floorboards / deck, then I always recommend putting sufficient mineral wool directly under the plates to make them distended. The fact they’re left raised up by the wool means that when the deck gets screwed down, the wool compressed and maintains the contact between the plates and the deck.

You’d need to spend an afternoon manually reshaping these to get the sag out of them, but no need whatsoever to discard them imho, just needs a bit of time and elbow grease. 
Leaving the PIR insulation where it is and fit the wool on top of it, as long as it won’t move south under compression of course. 

[ADringer]

46 minutes ago, Nickfromwales said:

If there’s no access from below, eg to staple the plates to the underside of the floorboards / deck, then I always recommend putting sufficient mineral wool directly under the plates to make them distended. The fact they’re left raised up by the wool means that when the deck gets screwed down, the wool compressed and maintains the contact between the plates and the deck.

You’d need to spend an afternoon manually reshaping these to get the sag out of them, but no need whatsoever to discard them imho, just needs a bit of time and elbow grease. 
Leaving the PIR insulation where it is and fit the wool on top of it, as long as it won’t move south under compression of course. 

Ok great, thanks.

 

The builder was happy to move the insulation up from below, but would wool be a better solution to ensure they are distended in this case?

[Nickfromwales]

14 minutes ago, ADringer said:

Ok great, thanks.

 

The builder was happy to move the insulation up from below, but would wool be a better solution to ensure they are distended in this case?

Yup. Doesn't look like you'd have room for another 20mm or 25mm of rigid insulation plus the wool? How much insulation is there out of curiosity?

[ADringer]

49 minutes ago, Nickfromwales said:

Yup. Doesn't look like you'd have room for another 20mm or 25mm of rigid insulation plus the wool? How much insulation is there out of curiosity?

 

We've actually got 100mm in there.

 

Sorry, I'm not completely understanding, should we move it up and put a little bit of wool just to push it out, or just wool?

[Nickfromwales]

3 minutes ago, ADringer said:

 

We've actually got 100mm in there.

 

Sorry, I'm not completely understanding, should we move it up and put a little bit of wool just to push it out, or just wool?

As per my last, I cannot work out what the current depth is between the top of the insulation and the underside of the floorboards? Only then can we advise

[Nickfromwales]

!00mm under a heated floor is barely scraping regs btw.

[ADringer]

15 minutes ago, Nickfromwales said:

As per my last, I cannot work out what the current depth is between the top of the insulation and the underside of the floorboards? Only then can we advise

Ah ok, I misread your last post!

 

Tbh we can't fit much more insulation between the joists if we are to put cabling in as well, best we can do with a retrofit.

 

I'll measure the gap when I'm at the house tomorrow, but from your previous message would it be along the lines of: greater than 20/25mm do insulation+ wool, otherwise just wool?

[ADringer]

34 minutes ago, Nickfromwales said:

!00mm under a heated floor is barely scraping regs btw.

Should probably also say this is first floor! Downstairs has 150mm

[Nickfromwales]

1 minute ago, ADringer said:

Should probably also say this is first floor! Downstairs has 150mm

OK, thanks.

 

18 minutes ago, ADringer said:

Tbh we can't fit much more insulation between the joists if we are to put cabling in as well,

Not at all ideal to be installing cables in that heated space.....  Have you consulted a sparky for compliance /de-rating the services etc?

 

20 minutes ago, ADringer said:

greater than 20/25mm do insulation+ wool, otherwise just wool?

As its 1st floor, just do wool tbh, as you're already within the heated envelope.

[ADringer]

5 minutes ago, Nickfromwales said:

OK, thanks.

 

Not at all ideal to be installing cables in that heated space.....  Have you consulted a sparky for compliance /de-rating the services etc?

 

As its 1st floor, just do wool tbh, as you're already within the heated envelope.

 

Cables are going underneath the insulation, not in the actual heated space, if that changes anything? So effectively sitting on the ceiling of below.

 

Yeah might get them to put wool down rather than push up every board from below. At least that will get the plates to point up 👍

[Nickfromwales]

1 minute ago, ADringer said:

 

Cables are going underneath the insulation, not in the actual heated space, if that changes anything? So effectively sitting on the ceiling of below.

 

Yeah might get them to put wool down rather than push up every board from below. At least that will get the plates to point up 👍

Ok, just not sure laying on the PB constitutes a "safety zone". Sparky should be able to decide that.

 

Yup, wool used to force the panels up about 20-25mm higher than top of joist should work well.

[ADringer]

14 minutes ago, Nickfromwales said:

Ok, just not sure laying on the PB constitutes a "safety zone". Sparky should be able to decide that.

 

Yup, wool used to force the panels up about 20-25mm higher than top of joist should work well.

Yeah don't quote me on that, sparky is coming in soon, that's just from what I've seen.

 

Cool, we'll do that, thanks for your help