Mako

Pros and Cons of PH

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so from you say  do we take it that really you have too many large windows  and or they really should have a solar radiation blocking coat on them to stop excessive solar gain inside the house?

 not pointed at you @Ferdinand directly ,but it does seem to be a re-occurring theme of houses over heating 

 

I have already been told by SWBO  that no mater what sort of MVHR is fitted she will still be opening the windows when ever she wants fresh air .

which makes me question for fitting it --and if house does store too much heat it can be balanced by windows being opened 

and as air quality will not be a problem  and at best  I probably only have another 20 years or less for independent living --then extra cost and complications of MVHR  is maybe not worth it

  and our intention for design is to have an orangery along the whole front of the house - and a similar thing above it - both will have real roof -- not glass 

 looking out over our view --that,s where we will go to cook in the sun  

 

 

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1 hour ago, scottishjohn said:

 

I have already been told by SWBO  that no mater what sort of MVHR is fitted she will still be opening the windows when ever she wants fresh air .

I thought the point of MVHR is that fresh air is being brought in continuously so you wouldn't want to open the windows. If you have MVHR and feel the need to open windows then the MVHR isn't set up correctly.

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6 minutes ago, PeterStarck said:

I thought the point of MVHR is that fresh air is being brought in continuously so you wouldn't want to open the windows. If you have MVHR and feel the need to open windows then the MVHR isn't set up correctly.

I am with you on this.

But, if people want to open windows, maybe because they like a breeze as well as fresh, but pollen and particulate polluted air, then they can.

Without MVHR, you only have one option, and that is to open windows.

1 hour ago, scottishjohn said:

so from you say  do we take it that really you have too many large windows  and or they really should have a solar radiation blocking coat on them to stop excessive solar gain inside the house?

Seems to be the case.  Architects seem to 'like light', and that has filtered down to peoples idea of normal (we don't want post 1973 oil crisis USA housing).  But since then we have upped air tightness and insulation levels, by law.  Add in more days over 30°C, and overheating can be a real problem.

I think people forget how powerful the sun is.  If the morning sun is low in the sky, but chucking out 300W/m2, and you have 4 m2 of openings that allows in 1200W.  Many modern houses only need that sort of input when it is cold.

Storm Alex has now hit me proper, my solar radiation is at 202W/m2.  Not dark.

@joe90 hope your pond is large, there is a lot of rain.

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5 minutes ago, SteamyTea said:

hope your pond is large, there is a lot of rain.


OH YES, in the rush to get it done I forgot to instal an overflow, the field around it is under water but way too wet to sort it this year. My “to do list” fir next year starts with overflow drain 🤣🤣🤣🤣.

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In my case I have a 12m long double glazed conservatory on the south side of the cottage with solar glass in the roof. Many told me on here I would over heat and yes in the middle of summer it did get to 35’ ( people pay to go on holiday to places that hot!!!) but I have large openable windows and doors so venting was achievable and we usually have a breeze. The bifolds into the kitchen and lounge can either be open (to heat the house) or closed to stop the house over heating or closed to stop house heating wasted in the conservatory and this works very well. In the shoulder months when the sun shines the conservatory heats the house and is a lovely place to sit. 
 

we have MVHR but like to open windows in the summer for the breeze and birdsong so I switch it off. In colder weather it’s on to give us fresh pre warmed air and no draughts.

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47 minutes ago, PeterStarck said:

I thought the point of MVHR is that fresh air is being brought in continuously so you wouldn't want to open the windows. If you have MVHR and feel the need to open windows then the MVHR isn't set up correctly.

I agree -- but no convincing the wife that it will  be 

she opens windows every day even if its below freezing outside -- 

So I think this is one battle I will avoid

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11 minutes ago, scottishjohn said:

she opens windows every day even if its below freezing outside -- 

Just the opposite of Wendy, who hates draughts and likes the whole house to be 23C/24C all day, every day, all year round.

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19 minutes ago, scottishjohn said:

So I think this is one battle I will avoid


been there, got the T shirt (I just turn the MVHR off). I turned it back on recently now it’s turned colder and the windows are shut.

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10 hours ago, Mako said:

am i right thinking that more concrete you have in the building the better?

if the concrete is accessible as a thermal mass?

 

The effect on energy saving of thermal capacity more than 100mm from the internal environment is very small and generally ignored, it takes to long (>24hrs) for the heat to get in/out.

 

 

10 hours ago, Mako said:

I believe the heating load should reduce as well, am I wrong thinking that?

 

Heating load is dependent on the rate of heat loss, i.e. a combination of fabric loss (U-values) and air infiltration rate (ach). The concrete would have to reduce one of these.

 

 

10 hours ago, Mako said:

my only worry with that system is due point reaching into the cellulose layer and creating condensation issues, mould growth, etc

how is the cellulose dealing with that?

 

Where walls are dominated by a single layer  the wall temperature and the dew point temperature move in step as we go through the wall. As long as the vapour resistance of the external containing layers are not more than the vapour resistance of the internal layers there should not be a problem.

 

Mako.jpg.c0fa9ea95aee4be1ca5982dde728cc37.jpg

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Posted (edited)
4 hours ago, scottishjohn said:

so from you say  do we take it that really you have too many large windows  and or they really should have a solar radiation blocking coat on them to stop excessive solar gain inside the house?

 not pointed at you @Ferdinand directly ,but it does seem to be a re-occurring theme of houses over heating 

 

 

I'd agree that it is a more recognised problem, but I would argue that it is a change that is still becoming known.

 

In another say 20 years it will be part of design practice, but the art of building develops slowly.

 

One favourite quote I always liked: The answer to wrong use is not disuse, but right use.

 

We still have people fitting trickle vents to solve condensation 🙂 . And presumably other people still use concrete pointing. Pneumatic tyres were invented just after the Penny Black, but I still had childhood friends with solid tyres on their bikes,  and I'm really young. Allegedly.

 

Quote

and our intention for design is to have an orangery along the whole front of the house - and a similar thing above it - both will have real roof -- not glass 

 looking out over our view --that,s where we will go to cook in the sun  

 

I'm planning a deep loggia or arcade across the S side of my house (which is unfortunately the road side but I can't bodily move it across the road, 'cos there's a house fthere already) for sun sitting, and breakfast, for my blueberry grove, some solar panels on the roof, and to keep more sun out of my study and no 2 lounge to stop them badly overheating occasionally.

 

I don't get a view of the Firth of Wotsit, however.

 

F

Edited by Ferdinand

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Inflation, oil running out, profiteering, upgrading networks, tax, draughts, increasing demand ..... 

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4 hours ago, Ferdinand said:

for my blueberry grove

Sounds interesting, I'll keep my eyes open for future pictures.

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2 hours ago, tonyshouse said:

Inflation, oil running out, profiteering, upgrading networks, tax, draughts, increasing demand ..... 

You've missed/hidden in mere "tax" the elephant in the room : government meddling. 

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Posted (edited)
52 minutes ago, PeterStarck said:

Sounds interesting, I'll keep my eyes open for future pictures.

 

I can help there.

 

Being the forum cheapskate, they are already in pots growing for a couple of years time. The aim is blueberries from late June to mid September, different foliage colours and varied flowers.

 

There is also a box, a blackberry and my previously neglected Fuschia which is kindly giving me a new flush of flowers after I apologised to it and extracted it from its sulking corner behind the bamboo.

 

EC7CBF5D-81A2-4DA3-B217-5FAA421C3C86.thumb.jpeg.e3750f6c59fe7bece337c03f3e0ae75f.jpeg

 

B92C537D-4C31-4B61-AEE4-45DBF4C8B5F4.thumb.jpeg.abff8f247ecfc3341832598f1d13a8f8.jpeg

Edited by Ferdinand
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1 hour ago, oldkettle said:

You've missed/hidden in mere "tax" the elephant in the room : government meddling. 

just to be clear on this, it is government meddling that has made energy so cheap for the last century

https://www.eesi.org/papers/view/fact-sheet-fossil-fuel-subsidies-a-closer-look-at-tax-breaks-and-societal-costs

 

A reduction in meddling  will drive up prices.

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17 hours ago, Mako said:

my only worry with that system is due point reaching into the cellulose layer and creating condensation issues, mould growth, etc

covered above

17 hours ago, Mako said:

 i also read somewhere that air-tightness is compromised after some time when the membrane joints start failing.

i'm sheeting mine internally with propassive osb and sealing all joints so no membrane, no failure also a service cavity.

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8 hours ago, scottishjohn said:

I agree -- but no convincing the wife that it will  be 

she opens windows every day even if its below freezing outside -- 

So I think this is one battle I will avoid

easily sorted and with the brucie bonus of less cost, buy fixed glazing.

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17 hours ago, Mako said:

, but building timber frame in this climate/humidity is challenging to keep the timbers dry as soon as they come out from the factory the humidity is at it. by the time you get it watertight its too late. i know i live in timber frame house and i swore never again.

build with i beams and not timber, more stable, less weight and less timber, win, win, win.

 

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1 hour ago, Simplysimon said:

build with i beams and not timber, more stable, less weight and less timber, win, win, win.

 

Pozi joists make 1st fix much easier than I-beams, but they’re not too much of a ball-ache ( if you own sharp hole saws and live drilling ). 
Can’t really think of a reason to go to I-beams vs posi’s TBH. 

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7 minutes ago, Nickfromwales said:

Pozi joists make 1st fix much easier than I-beams, but they’re not too much of a ball-ache ( if you own sharp hole saws and live drilling ). 
Can’t really think of a reason to go to I-beams vs posi’s TBH. 

walls and roof with service cavity no issues with drilling

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12 minutes ago, Simplysimon said:

walls and roof with service cavity no issues with drilling

I have worked on houses using I beams for the first floor, and you have a lot of drilling of the web for things like MVHR ducts, you would need some "service void" to avoid that.  and if you need to drill larger holes, e.g. for drain pipes, you will probably have to use gusset plates as well.

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@Simplysimons original comment was meant as in - build the frame from i joists I think. Wasn't exclusively referring to floors

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3 hours ago, joth said:

just to be clear on this, it is government meddling that has made energy so cheap for the last century

https://www.eesi.org/papers/view/fact-sheet-fossil-fuel-subsidies-a-closer-look-at-tax-breaks-and-societal-costs

 

A reduction in meddling  will drive up prices.

 

The paper seems to be about the US. I don't buy claims about trillions in negative externalities, the rest of "subsidies" seems to have trivial value if you look at the size of the industry.

 

More importantly, here the consumption of energy is heavily taxed so cannot see the relevance of your link. 

 

Everything government does makes things more expensive, if not immediately then in the long run. 

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Posted (edited)
20 hours ago, Mako said:

what happens if you use concrete in walls and suspended floors? if i understand your calks you converted walls only

 

If you increase specific capaicty to 204 Wh/K which is suggestion in PHPP for a concrete box, then not much changes

 

Quote

do we anticipate heating  the concrete mass by solar gains in the winter?

I believe the heating load should reduce as well, am I wrong thinking that?

 

No, why should it?  Heating load is energy needed heat house on coldest day.  The coldest day is winter is unlikely to have much sun heating the house.

 

Quote

sound proofing, I thought soundproofing is also improved by concrete, living in timber frame house now, I can hear everything

through the walls.

 

Are comparing 75/89mm internal studwork with (if you're lucky) some rockwool with 300mm external studwork full of celulose?  Also consider that a 140mm external timber-frame wall with PIR does not perform nearly as well in terms of noise or decreement delay as a 30mm twin-stud wall with celouse.

 

Quote

sustainability point of concrete v timber, if you look at the life span of timber frame builds being around 50years, concrete buildings

are here already for hundreds of years. surely concrete must be more sustainable compared to timber. 

 

I don't think many people would agree with 50yr lifespan at all, lot of historic building are timber frame and timber frame is used very widely in a lot of place in the world.

 

 

 

Edited by Dan F

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Posted (edited)
20 hours ago, Mako said:

my only worry with that system is due point reaching into the cellulose layer and creating condensation issues, mould growth, etc

how is the cellulose dealing with that?

 

I'm not an expert, but this is dealt with by the wall make up being vapour permeable.  Typically the external board/membrae is something like:

https://mdfosb.com/en/medite/products/medite-vent

https://www.ecologicalbuildingsystems.com/product/solitex-fronta-humida

 

This stops water getting in and let's vapour get out.  A vented cavity is needed externally to allow this.

 

 At the same time, an internal airtight board/membrane stops air/vapour being tramsmitted from house to wall.

https://mdfosb.com/en/smartply/products/smartply-propassiv

 

I think you are potentially imagining a problem, that is actually already been worked out?

 

 

Edited by Dan F

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