# Pros and cons; underfloor heating, pumped cavity insulation and concrete first floor



## Brigid (2 Jan 2011)

Hi,  we hope to start excavating and building soon.  Our engineer has asked us to let him know if we want to go for the above.  There seem to be pros and cons to each and I am really not clear on what they are.  I am going to set out hereunder my questions and if anyone can shed light on any aspect I'd be really grateful. Many thanks. 

Underfloor heating.

Pros
A lovely warm ambient heating.
No unsightly radiators

I am not too sure of the cons! 
People talk about expense of them but is that in the installation or the running costs.  If you run it off a condenser oil burner is it any different than the cost of running radiators.

I understand the 'con' in terms of the length of time for it to reach the desired temperature or reduce.

Is there a danger of pipes leaking under floor as time wears on?


Pumped cavity insulation.

Our engineer has suggested that we go for this but from asking friends they have raised the following issues:

1. with time the cavity beads can sink to the bottom of the cavity wall leaving gaps above.
2. where does the moisture or condensation go and could it result in mould or the disintegration of the bonding glue.
3. it is too new as technology to be sure that it will stand the test of time and it woudl be better to go for the rigid option.
4. is it less expensive than the rigid insulation? (obvioulsy that woudl be a positive)


Concrete slabs on first floor.

I understand that it is a better fire retardant and gives proper sound proofness... but how much more expensive is it on average than the wooden floor joists option?  Our engineer has said that when you toss it all up it would be only about 2.5K but a friend who completed a self build recently said he thought that by the time you have put in reinforced foundations and laid the blocks flat on the internal walls and the extra labour that would entails that you are looking more at 10K.  I know that this is all relative to the size of the house but what is the general feeling out there?  also concrete slabs reduces flexibility at a later stage if you want to make any changes.

Many thanks for any insights or experiences you might be able to give.


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## esox (2 Jan 2011)

> Underfloor heating.


 
you've got most of the important points to do this form of heating, the running costs are sightly more than traditional radiator system, I personally think the benefits out weigh this issue.

1. comfort if you like a lovely toasty warm house ufh
2. control if you would like to set accurately the temp of each individual room ufh
3. design if you don't want any restrictions on where to put furniture/lockers ufh

the beauty of ufh is it runs at low temp which suits the modern condensing oil/gas boilers also to future proof you system leave a duct from the ufh manifold to outside the house (4" sewer pipe) should the technology of electric or geothermal heating improve or become cost effective you can be connected up without much hassle


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## onq (2 Jan 2011)

Brigid,

You are now asking detailing questions of your engineer that he simply is not competent to advise upon.
Structural engineers are experts on structural, foundation and drainainge matters.
However, in terms of weathering and working drawings they offer basic levels of details and drawings.

These details are intended to inform the architect about the structural strategy.
They are not sufficient to inform a builder how to properly detail and weather a residence or compliantly insulate, seal and build it.

You don't appear to have begun to consider the implications of an mVHR system - an essential part of strategy.
It seems clear you are determined to press ahead without an architect, despite the best advice available on AAM.
Believe me when I say that proceeding to site while you're still asking basic questions like this is a recipe for disaster.

ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon              as a defence or support - in and of itself - should legal      action    be      taken.
Competent legal and building professionals should be asked to advise in              Real Life with rights to inspect and issue reports on the      matters    at      hand.


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## onq (2 Jan 2011)

esox said:


> you've got most of the important points to do this form of heating, the running costs are sightly more than traditional radiator system, I personally think the benefits out weigh this issue.
> 
> 1. comfort if you like a lovely toasty warm house ufh
> 2. control if you would like to set accurately the temp of each individual room ufh
> ...



Weren't you asked to supply more information in another thread esox?
Am I confusing you with someone else?

Why no I'm not - it was this thread about insualted fonudations.
http://www.askaboutmoney.com/showthread.php?t=148373
I asked you to post more information.
Whats' the story?

ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon               as a defence or support - in and of itself - should legal       action    be      taken.
Competent legal and building professionals should be asked to advise in               Real Life with rights to inspect and issue reports on the       matters    at      hand.


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## Brigid (3 Jan 2011)

Esox, thank you for that - that is a good idea to future proof the place if we decide to lay the pipe work; we are still not sure. Many thanks.


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