Softening the feel of a concrete slab floor

[saveasteading]

If I may enter this.

Passivhaus is good for providing strict, proven  methods and attention to detail.

Far too many houses are flawed because of corners being cut, lack of attention to detail, and basically not being a holistic design. So an option for control of this is a good thing.

 

My own choice would always be to design the building I want. If that means that the big windows face south for the view, and have bifolds, then that is the priority.

A wood burning stove too, if in the country.

Then make it work efficiently, but appreciate that sometimes the doors will be left open, or the windows opened on a whim.

But I don't trust 'others' to get it right and so I interfere and observe throughout. Not everyone can do that.

 

And then there is the cost. It isn't available to everyone.

 

Passivhaus is good design. Non Passivhaus can be good too, perhaps even better.

 

 

 

 

 

 

[Gus Potter]

On 25/04/2023 at 22:43, nod said:

If you are fixing matting to timber Use Ardex Absolutely Bombproof 

Thanks for the guidance. Think you also mentioned Schluter ditra.. a while ago.. you can deduce I'm making slow progress with my bathroom.

[nod]

Slow is still good 

 

Ditra is really good 

I’ve never had any issues with it 

[Gus Potter]

On 30/04/2023 at 00:29, IanR said:

What is it about Passivhaus principles that you feel run contrary to how people live day to day? and is that somehow related to your notion that that a PH home would be unable to maintain a comfortable temperature during a harsh weather event, such as "the beast from the east"?

Good question.

 

I'm very supportive of the Passivhaus principles and when I get a chance use that as a benchmark. I don't think I said that I was disagreeing with the principles was just pointing out how you may suffer disappointment.. with a bit of "drama" at my end. Hope the following helps you see where I'm coming from as discussion is healthy. I can see why you are asking and probing my argument.

 

I'm always wary about accreditation schemes, not that they are wrong but they often attract cost. An example here would be the CE marking of structural steel products. There were plenty great fabricators in the UK who could turn out safe buildings.. they got lumbered (mixing materials here) with a lot of cost ( I know as I helped set up the CE marking scheme for a steel fabricator) and all this was passed onto the consumer. In some ways the CE marking for steel is good as it it to do with structural safety.. but a Passivhuas does not pose a structural risk.. of death.

 

If you want an accredited Passivhuas then you have to comply. The earlier schemes and accreditation process was confining and carried additional cost.. part of the cost coming from the suppliers and all this was passed onto the consumer. That was a pity as the concept and intent was and still is admirable... but the reality was that only the well off could afford to be environmentally friendly.

 

Also, the earlier schemes did not really consider embodied carbon, whole life cycle ( BS requires 50 years.. lenders often use 60 years as a benchmark, maintenance cost.. also a biggy.. and a massive elephant in the room) , loss of material performance.. and how homes are used by say a family of two adults, two or three kids..a dog /cat.. then by say an elderly gent.. and then by another owner.. long list.

 

The Passivhuas Trust publish plenty papers but one from last year (May 2022) lets you see how they are dealing with and advancing on the "environmentally cost neutral house" rather than one which is just cost neutral to heat and keep at an even temperature. But also.. as Build Hubbers we would be a bit unchuffed if we thought what we are building is only going to be seviceable for 50 years.. where is your pride folks?

 

The biggy here for me is that when I design a house I try and think.. yes we want it to be environment friendly / not fall down.. keep the bils / running costs down but we also need to design in such a way that the house holds it's value, is it easy to and cheep to maintain (can we source parts, can local folk fix things that go wrong) , can it be heated up if old folk visit, it snows and the kids are opening the doors. OR do we want to spend all that money just so the house can get some kind of accreditation or just look good on paper?

 

@IanR I can see I may have rubbed you up the wrong way here, sorry for that. But if we design for say "difficult me" to make it a home it means that we need to over design and right there is where I think we are of a different view. If you over design a boiler the system is not efficient for example... but what price are do we pay for that luxury and how can we offset that intermittant price?

 

What about those big ticket items.. 3g glazing.. have you checked the guarentee on the glazed units.. maybe they are under warranty for 7 -10 years? What then? I could go on at length but I summarise below and look forward with encouragement. Have you checked the roof warranty.. zinc cladding in a coastal zone? Now if the roof has to be redone that is NOT  "Passive" in Cornish etc terms.

 

The building regs are changing a lot in the wording. Previously they used to be along the lines of .. you must do this.. now it is.. well there are opprotunities to innovate and here are the targets you have to meet.. the future looks exciting as we can put forward all sorts of designs and ideas!

 

@IanR I don't doubt your house suits you and if you are getting that stable temperature then well done.. you have made a good job. But please recognise that you may not be the only occupant.. in fact.. you have probaly built a house that will stand for well over a 100 -150 years.. yes you own it now but be proud of your hard work and the legacy you will leave.

 

 

 

 

 

 

 

[IanR]

On 04/05/2023 at 20:11, Gus Potter said:

@IanR I can see I may have rubbed you up the wrong way here, sorry for that.

 

Not at all, you made a peculiar statement about passive houses being cold in extreme weather events and then expanded further on you feeling there is a need to balance passive house principles with how people live from day to day. I was actually just interested in why you'd have such an opinion.

 

Trying to boil down your reply, it seems you want to be able to push up the heating in a house, at certain periods, above a typical ambient temp for reasons of comfort, but you feel "over-sizing" the heating system in a passive house, in order to do so, would lead to an inefficient heating system, but doing the same in a non-passive house wouldn't.

 

Since the power required to heat the hot water if often higher than it takes to cover the space heating requirement in a passive house, even on the coldest of days, heating systems tend to be over-sized anyway.

 

I believe the rest of the points you make are really related to the choices you make as a self-builder, rather than anything specific to a passive house. It's up to the self-builder to determine if those choices are good value for them. 

[joe90]

Well, interesting thread, fir my part I designed a house which was well insulated firstly, only double glazing in wooden frames as the coatings used are not far short of triple glazing figures, I did no calculations whatsoever, purely guesswork, small ASHP off EBay (which could be switched out fir a bigger one if required in the future), bifolds. MVHR, UFH. The house only needs heating for a couple of months of the year, the rest of the time it’s completely stable, woodburner for upping the lounge temp if required (and a nice feeling when looking at the cold outside ) No heating upstairs (apart from electric towel rads and electric UFH for warm toes after bath/shower). IF a bedroom needs heating (old people or illness) a simple plug In heater raises the temp very quickly and it lasts (not had to do this yet). I would never consider a certificate fir being passive but I can simply show anyone the very low electricity bills throughout the year,  what’s not to like 🤷‍♂️

[Iceverge]

A house is like a boat and a passive house is like a boat with no holes in it.  

 

I can never underestimate why people argue that a boat would be better with holes in the hull. 

 

You can still fit whatever engine you like. 

 

 

[Alan Ambrose]

>>> Softening the feel of a concrete slab floor

 

Out of curiosity, I visited the battersea power station building yesterday. I swear the concrete slabs they were used for 1st floor and above flooring had some give to them. Is there such a thing as concrete and rubber crumb mix?

 

Ah, I see there is:

 

https://www.theengineer.co.uk/content/news/crumb-rubber-from-end-of-life-tyres-recycled-into-concrete/

 

Edited May 8, 2023 by Alan Ambrose

[Sparrowhawk]

Thanks for that Alan - I've not had a chance to visit Battersea yet.

Do screeds have a different feel to concrete, or are they merely a different concrete mix?

[saveasteading]

28 minutes ago, Sparrowhawk said:

Do screeds have a different feel to concrete

They are all hard enough for us not to notice.

[JohnMo]

On 25/04/2023 at 22:23, Iceverge said:

@JohnMo has recently put UFH over insulation below 2 x layers of OSB floating. I am very interested in this approach. No wet trades. No crucifying hammering of your joints. 

Some feedback as we now have the finished floor finish in place.

 

Reminder of floor build-up

Council concrete paving slabs (3' x2') bedded on 50 to 70mm concrete

50mm EPS70

DPM

100mm EPS70 in two layer with staggered joints

50mm EPS UFH profile boards, with 50mm battens at 400mm centres in between and a perimeter batten in 50mm.

2x 9mm OSB (staggered joints and fully glued) screwed to battens

 

Due to the floor not being perfectly level (low spot in middle of floor), the floor was topped in a fibre reinforced self levelling screed, with a max depth of 10mm down to nothing.

 

Thin foam underlay and 10mm laminate click and lock flooring added.

 

Floor feels solid with a little give. But is a little softer in feel underfoot to our 100mm concrete on 200mm PIR, with a 20mm wooden floor bonded to it, in the main house

[saveasteading]

37 minutes ago, JohnMo said:

A little softer in feel underfoot to our 100mm concrete 

Do you mean that it deflects under your foot, or generally?

[jack]

I'm very late to this but we have an insulated concrete raft: up to 300 mm EPS, ~100 mm concrete slab, then ~70 mm polished concrete screed (no insulation between structural slab and screed).

 

I work from home and almost never wear shoes inside, so I spend a lot of time walking around on it in socks. Yes, it feels hard underfoot, but to be honest I don't notice it.

 

As for temperatures, I had dinner at a friend's place mid-winter many years ago. It was a refurb with building regs insulation levels throughout. Top level was engineered oak flooring. I don't know what flow temperature they were using, but I found it extremely uncomfortable underfoot. My feet were sweating and I found it extremely distracting. TBF, my wife didn't notice the temperature.

 

Our floor temp slowly wobbles around 19.5-21.5 degrees during winter, based on a 25-28 degree (weather conpensation dependent) flow temp. It doesn't feel warm underfoot, but it's perfectly comfortable to walk around in socks.

[JohnMo]

24 minutes ago, saveasteading said:

Do you mean that it deflects under your foot, or generally?

Neither really deflects under foot, so generally.  Not had the UFH heating on for long enough to an idea of feel of the floor from that perspective. 

[Iceverge]

1 hour ago, JohnMo said:

Some feedback as we now have the finished floor finish in place.

 

Reminder of floor build-up

Council concrete paving slabs (3' x2') bedded on 50 to 70mm concrete

50mm EPS70

DPM

100mm EPS70 in two layer with staggered joints

50mm EPS UFH profile boards, with 50mm battens at 400mm centres in between and a perimeter batten in 50mm.

2x 9mm OSB (staggered joints and fully glued) screwed to battens

 

Due to the floor not being perfectly level (low spot in middle of floor), the floor was topped in a fibre reinforced self levelling screed, with a max depth of 10mm down to nothing.

 

Thin foam underlay and 10mm laminate click and lock flooring added.

 

Floor feels solid with a little give. But is a little softer in feel underfoot to our 100mm concrete on 200mm PIR, with a 20mm wooden floor bonded to it, in the main house

 

Good to hear. 

 

What would you attribute the slight dip to? 

 

I'd have thought 2 X 9mm might be a bit thin without the battens. The Avantech details from the US suggests 2 X ¾ layers.  What do you think?

[JohnMo]

Not sure on the dip cause.

 

Without battens 2x3/4 would be better.

[Wil]

20 hours ago, Sparrowhawk said:

Thanks for that Alan - I've not had a chance to visit Battersea yet.

Do screeds have a different feel to concrete, or are they merely a different concrete mix?

If you ever do come to Battersea, send me a DM, I’m around here 4 days a week… haven’t noticed any bouncy floors though…

Edited May 9, 2023 by Wil