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Cheap 6KW ASHP


PeterW

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Sorry, I can't read the image on this screen.

 

To get the U values for the walls, floor, roof etc, you need to work out the impact of all the materials, plus any sealed air gaps.  The method for doing that is obtain the lambda value for the material, work out the thermal resistance for each layer, add up all those thermal resistance figures, and then take the inverse to find out the total U value.

 

I have some simple U value calculators to do this for common building materials (timber, OSB, plasterboard, sealed air spaces, insulation materials, concrete, stone etc) but rather than guess, if you can give the build up of the walls, ground floor and either the ceiling or roof (depending where the insulation is) I can then post back here the calculation for all to see and use.

 

 

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3 minutes ago, JSHarris said:

I have some simple U value calculators to do this for common building materials (timber, OSB, plasterboard, sealed air spaces, insulation materials, concrete, stone etc) but rather than guess, if you can give the build up of the walls, ground floor and either the ceiling or roof (depending where the insulation is) I can then post back here the calculation for all to see and use.

 

@JSHarris i am very grateful for your offer to help me with this,  i will compile the information in the next few days and report back. Thanks. 

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14 minutes ago, Cpd said:

@JSHarris i am very grateful for your offer to help me with this,  i will compile the information in the next few days and report back. Thanks. 

 

No problem, if you include the window and door areas and U values I can work through the heat loss spreadsheet pretty quickly, and give some more useful data for you.

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@willbishNo it is due for delivery in the next few days..... was just reading through @PeterW recomendation https://www.wundatrade.co.uk/shop/home/20mm-eps-400-overfloor-board/

and just trying to work out the best possible outcome with a MAX floor build up of 130mm 

so far i had 

Insulation 90mm (probably two layers with cross battens) attached to floor

Some sort of sub bace wood under floor 18mm attached to battens 

Wunda underfloor heating board  20mm glued to sub. Floor 

But that only leaves me with 2mm ! For my final floor coverings! Go figure

was just about to go back to the various threads on floor coverings and see what my options are. 

Would really like to use the underfloor heating option downstairs, sure it would satisfy  @Nickfromwales a bit better than the large radiators i had thought about..... 

still working on a bunch of data for @JSHarris to help me with actual heat requirments, nearly there.

its a long project but i want to get it as close to right as i can and the help here is just fantastic and a little humbling. 

 

 

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24 minutes ago, Cpd said:

Insulation 90mm (probably two layers with cross battens) attached to floor

Some sort of sub bace wood under floor 18mm attached to battens 

 

Not needed..!

 

Gun foam will stop the boards moving anywhere - then tag the  EPS onto the PIR with more foam. They can’t move about so don’t panic. 

 

Then its either wood or tile over the top, 18-20mm to play with is ample. 

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@PeterW i geuss i am always over engineering things...... comes from spending a lifetime  building stuff that has a life expectancy of hundreds of years..... photo example. Unless its “bomb proof” i start to worry...... just got to get over it as best as i can. My idea with the 6mm ply was to try and get a slightly more robust feel to the floating floor. Whats your opinion..... i can take it. 

 

Down stairs Floor build up living area  aprox 4.8 x 4.3m 

Concrete slab 

Calotex 90mm Bonded to flooor with foam 

20mm underfloor heating pipe boards bonded to Calotex with foam

Thin underlay as recomended  by heating board website...... 

possible 6mm ply floating on underlay 

16mm solid strand, tongue and groove bamboo flooring fully bonded to ply with flexible something or another.....  

 
I have not come to a conclusion about the kitchen area  4.12m  x   4.3m (considering tiles as i have quite a lot) or the open corridor  4.3 x 0.9m that leads from the front door directly to the stairs on far side of building, was considering some sort of stone slab Effect as it is only 5m long x 900mm wide and will be where the coats and boots get dumped... 
more research into this. 
 
Could you recomend the type of foam as i have only used  Siroflex Expanding Foam, Gun Grade. 
Not rushing into this as i will need to buy materials as and when i can afford them but i want to know exactly what i am going to use, where it will come from and how much it will cost. 
As always. Thanks 

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32 minutes ago, Cpd said:

 

Down stairs Floor build up living area  aprox 4.8 x 4.3m 

Concrete slab 

Calotex 90mm Bonded to flooor with foam 

20mm underfloor heating pipe boards bonded to Calotex with foam

Thin underlay as recomended  by heating board website...... 

possible 6mm ply floating on underlay 

16mm solid strand, tongue and groove bamboo flooring fully bonded to ply with flexible something or another.....  

 
I have not come to a conclusion about the kitchen area  4.12m  x   4.3m (considering tiles as i have quite a lot) or the open corridor  4.3 x 0.9m that leads from the front door directly to the stairs on far side of building, was considering some sort of stone slab Effect as it is only 5m long x 900mm wide and will be where the coats and boots get dumped... 
more research into this. 
 
Could you recomend the type of foam as i have only used  Siroflex Expanding Foam, Gun Grade. 
Not rushing into this as i will need to buy materials as and when i can afford them but i want to know exactly what i am going to use, where it will come from and how much it will cost. 
As always. Thanks 

 

 

Not sure how thick the slab is, so I'll assume 100mm - if it's different it's easy enough to change the thickness and recalculate.

 

From the bottom up:

 

100mm thick concrete with a λ of ~1.5 W/m.K gives an R value of 0.1m * 1.5 W/m.K = 0.6667 m².K/W

 

90mm thick PIR foam with a λ of 0.023 W/m.K gives an R value of 0.09m * 0.023 W/m.K = 3.913 m².K/W

 

20mm UFH boards, λ unknown, so assume same as EPS 200, 0.034 W/m.K gives an R value of 0.02m * 0.034 W/m.K = 0.5882 m².K/W

 

Assume 4mm foam underlay with a λ of 0.034 W/m.K gives an R value of 0.004m * 0.034 W/m.K = 0.1176 m².K/W

 

6mm ply with a λ of 0.15 W/m.K gives an R value of 0.006m * 0.15 W/m.K = 0.05333 m².K/W

 

16mm bamboo with a λ of 0.15 W/m.K gives an R value of 0.016m *0.15 W/m.K = 0.1067 m².K/W

 

Adding all the R values above gives:

 

0.6667 + 3.913 + 0.5882 + 0.1176 + 0.05333 + 0.1067 = 5.4455 m².K/W

 

Taking the inverse of the R value gives the U value:

 

1 / 5.4455 m².K/W = 0.1836 W/m².K

 

 

For bonding foam together, then any low expansion gun foam will work well.  My personal preference is the Soudal stuff, but there's very little to choose between any of the low expansion foams.

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  • 1 month later...

Just an update.

Have been busy working out and recording all the existing and intended layers of materials that make up my cottage, this will (with a bit of help) will give me the details i need to enter the data into Jeremys spread sheet and work out my space heating requirements. 

 

I am now trying to get all my ducks lined up to go hard at it this spring and summer with the hope that the end will be in sight by the end of summer...... 

 

I overstepped by making it unliveable in the frustration that is caused by scratching round the edges and now need to get things back under control. 

 

The very basic idea is to re insulate the inside with calotex and then osb and plaster board, obviously there is a lot more to it than that but dont want to bore you all to death with my long lists of wall and ceiling build ups....

 

But the short of it is 

Walls 

Ventilation gap between outer stone work and inner framing

50 x 70mm internal framing infilled with calotex 

70mm calotex over frame

Osb

Plasterboard

 

The upstairs has Vaulted ceilings and these have been filled with 170mm of calotex with a further 25mm over the rafters, osb and plasterboard

 

When i have worked out my heating requirments with the help of Jeremys spread sheet i will then start to look into the  UFH layout and DHW.

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