ᐅ Wall thickness? Facing brick / insulation? Cavity wall with 3D steel tie system / render
Created on: 15 Feb 2010 19:39
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doberman123D
doberman12315 Feb 2010 19:39I’m new to the house-building forum and wanted to say hello here!
Now to my issue: in about 2-4 years, my future wife and I want to build a house (solid construction). We’ve already chosen a model from a prefabricated house supplier, but we want to replicate it ourselves since it would only be affordable with our own labor. I’ve been working on a rough cost calculation for the past 1-2 weeks and need help with insulation.
The exterior wall of the house is planned to be made of facing bricks/clinker bricks measuring 240*115*71 mm (9.4*4.5*2.8 inches) NF size, followed by insulation — which is where I have no knowledge (this is my problem) — and the interior wall is planned as a solid block (KSS) 240*175*113 mm (9.4*6.9*4.4 inches) 3 DF, laid lengthwise to reach a thickness of 240 mm (9.4 inches), finished with plaster, which I think is about 15 mm (0.6 inches) thick unless I’m mistaken. Without the insulation, the wall thickness would be approximately 370 mm (14.6 inches) so far.
If someone could also provide a suitable price per square meter for their suggested solution, that would be perfect, but it’s not a must. If I know what to look for, I can figure it out myself.
Like most people, we want to save energy costs (around 280 m² (3,014 ft²)) and would like a house with a U-value matching a KfW 60 standard, preferably even as low as KfW 40. Of course, standards could change in 2-4 years and these requirements might no longer be sufficient, but they are good enough for initial calculations. It’s also about qualifying for subsidies and so on.
I have already tried using a U-value calculator, but I struggled with selecting the right parameters to enter there.
I would appreciate any help or suggestions in this regard.
Best regards, doberman123
Now to my issue: in about 2-4 years, my future wife and I want to build a house (solid construction). We’ve already chosen a model from a prefabricated house supplier, but we want to replicate it ourselves since it would only be affordable with our own labor. I’ve been working on a rough cost calculation for the past 1-2 weeks and need help with insulation.
The exterior wall of the house is planned to be made of facing bricks/clinker bricks measuring 240*115*71 mm (9.4*4.5*2.8 inches) NF size, followed by insulation — which is where I have no knowledge (this is my problem) — and the interior wall is planned as a solid block (KSS) 240*175*113 mm (9.4*6.9*4.4 inches) 3 DF, laid lengthwise to reach a thickness of 240 mm (9.4 inches), finished with plaster, which I think is about 15 mm (0.6 inches) thick unless I’m mistaken. Without the insulation, the wall thickness would be approximately 370 mm (14.6 inches) so far.
If someone could also provide a suitable price per square meter for their suggested solution, that would be perfect, but it’s not a must. If I know what to look for, I can figure it out myself.
Like most people, we want to save energy costs (around 280 m² (3,014 ft²)) and would like a house with a U-value matching a KfW 60 standard, preferably even as low as KfW 40. Of course, standards could change in 2-4 years and these requirements might no longer be sufficient, but they are good enough for initial calculations. It’s also about qualifying for subsidies and so on.
I have already tried using a U-value calculator, but I struggled with selecting the right parameters to enter there.
I would appreciate any help or suggestions in this regard.
Best regards, doberman123
D
doberman12315 Feb 2010 20:22Insulation Material
I found an insulation material but I’m not sure if the thermal conductivity value of 0.032 for the insulation boards (200mm (8 inches)) plus 370mm (14.5 inches) would be sufficient to achieve the total wall thickness for my 40 KfW house... just considering the walls!!
I still need to look into the roof and the base/foundation...
INSULATION BOARDS EPS-F Plus 200mm
The best insulation material for high-performance requirements is Austrotherm EPS F-PLUS. This facade insulation board exceeds the insulation capability of traditional boards by more than 20%. The gray boards are also suitable for tight spaces, for example at window sills or cornices.
Specifications:
Cell content: Air
Product type: according to ÖNORM B 6000 EPS F; system-tested according to ETAG 004
Effective dimensions (LxW): 1000 x 500 mm (39 x 20 inches), thickness 200mm (8 inches)
Usable surface area: 0.50 m² (5.4 ft²) per board
Tensile strength: 150 kPa (15 t/m²)
Thermal conductivity (Lambda) »n = 0.032 W/(mK)
Fire resistance class: B1 (flame-retardant)
Packaging: 2 pieces per bundle / 1 m² (10.8 ft²) per bundle
Approximately 100 boards (50 m² (538 ft²)) are available
PRICE: EUR 15 per m²
EUR 750 for 50 m²
I found an insulation material but I’m not sure if the thermal conductivity value of 0.032 for the insulation boards (200mm (8 inches)) plus 370mm (14.5 inches) would be sufficient to achieve the total wall thickness for my 40 KfW house... just considering the walls!!
I still need to look into the roof and the base/foundation...
INSULATION BOARDS EPS-F Plus 200mm
The best insulation material for high-performance requirements is Austrotherm EPS F-PLUS. This facade insulation board exceeds the insulation capability of traditional boards by more than 20%. The gray boards are also suitable for tight spaces, for example at window sills or cornices.
Specifications:
Cell content: Air
Product type: according to ÖNORM B 6000 EPS F; system-tested according to ETAG 004
Effective dimensions (LxW): 1000 x 500 mm (39 x 20 inches), thickness 200mm (8 inches)
Usable surface area: 0.50 m² (5.4 ft²) per board
Tensile strength: 150 kPa (15 t/m²)
Thermal conductivity (Lambda) »n = 0.032 W/(mK)
Fire resistance class: B1 (flame-retardant)
Packaging: 2 pieces per bundle / 1 m² (10.8 ft²) per bundle
Approximately 100 boards (50 m² (538 ft²)) are available
PRICE: EUR 15 per m²
EUR 750 for 50 m²
D
doberman12315 Feb 2010 20:38Insulation
Who is actually responsible for calculating the insulation of the house? Is it an architect who is also in charge of the structural engineering and similar aspects, or how does this process usually work?
Who is actually responsible for calculating the insulation of the house? Is it an architect who is also in charge of the structural engineering and similar aspects, or how does this process usually work?
6
6Richtige15 Feb 2010 22:15Hello doberman123,
KfW 40 or 60 standards no longer exist.
If you want to replicate them, I would be cautious—is there manufacturer approval for that?
Which cost estimates for which trades have you prepared so far?
What professional qualifications do you have?
What liquid funds are available?
What total costs have you calculated?
What does the zoning plan or building permit say about your planned house—are you even allowed to build it that way?
Once you have clear answers to all these questions, we can take it from there.
KfW 40 or 60 standards no longer exist.
If you want to replicate them, I would be cautious—is there manufacturer approval for that?
Which cost estimates for which trades have you prepared so far?
What professional qualifications do you have?
What liquid funds are available?
What total costs have you calculated?
What does the zoning plan or building permit say about your planned house—are you even allowed to build it that way?
Once you have clear answers to all these questions, we can take it from there.
D
doberman12317 Feb 2010 00:49Calculation + Open Questions
Hello 6 Richtige,
thanks for your reply!
So, let’s take a look at what I’ve put together so far. I hope I haven’t made any major calculation errors, and I’ll just shoot from the hip...
Professional qualifications:
I am an electrician (currently working in switchgear construction). My brothers are a gas/water installer and a bricklayer by trade.
My experience with house construction is limited to working as an electrician on site and having installed roof tiles on three roofs... same goes for my brothers.
We have also helped build two more houses (for our parents) with the help of relatives, though we were still too young back then to do much besides roofing. At construction sites we usually work in groups of three to four (1-2 bricklayers and 2 laborers), and if more people need to be on site for a few days, I can arrange that.
Costs:
Interior walls + 1 outer shell with 700m² (7500 sq ft) of wall surface using KSS 3DF blocks—I don’t plan to lay them crosswise anymore because KSS has a high thermal conductivity, so I might add more insulation instead.
Cost for 3DF blocks: 1000 units cost €416, with about 30 blocks plus mortar per m², so the calculation is: 700*30/1000*416 = €8,763
For facing bricks / clinker bricks, I couldn’t find exact prices, so I’m estimating €30 per m², which makes 30*700 = €21,000
Mortar price per kilogram is €0.08 including VAT, needing 18kg for 1m², so 700*18*0.08 = €1,008
I simply doubled that considering the smaller facing bricks, so approximately €2,000
An integrated conservatory (sunroom) costs around €25,000
Stairs: €15,000
Interior finishing: €20,000
Windows & doors: €20,000
Roof: 350m² (3767 sq ft). I read somewhere that a pitched roof (30 degrees) costs between €75 and €100 per m². I’m going with €100 (not sure if this includes labor or if it’s accurate), so 350*100 = €35,000
Regarding insulation, I have read a lot—from “not worth it” to “absolutely necessary.” I have no idea which materials or construction substances last longer than 25 years. Some products have a stated lifespan of 25 years, which would be terrible if I had to remove the facing bricks after that period. It would definitely be better to have good insulation, especially since heating 280–300m² (3014–3229 sq ft) would get expensive over time.
That leads to the question of whether it’s worthwhile to insulate properly in order to get a better loan for insulation materials and heating systems. The more and cheaper the conditions, the better the cost-benefit ratio. So I’m also asking about available KfW housing standards—are there KfW 40 or 60 levels? What about KfW 55?
Well, I still need to research what kind of insulation and heating systems make sense—heat pumps, solar thermal, etc.
Still to determine are the material costs for:
Insulation of walls, slab, and roof?
Heating systems?
Concrete slab?
Foundation slab?
Right now, excluding insulation, heating systems, and electrical work, the total material cost is €146,736, which I think is quite generous for a house measuring 18m x 17m x 7m (59ft x 56ft x 23ft).
If these approximate numbers hold, that’s around €140,000 so far, as quantity discounts will likely apply.
The local development plan is “okay” according to the architect (said while drinking).
The house is similar to a prefabricated house but not even 50% identical—I mention this just so anyone curious can roughly imagine the floor plan.
Equity is between €30,000 and €40,000, plus land of approximately 1300–1600m² (14000–17200 sq ft).
Total material costs should not exceed €170,000, leaving about €20,000 to €30,000 for insulation, heating systems, electrical work, and concrete slab/foundation.
Total construction costs should be max around €200,000 to €220,000.
Construction time estimated at roughly 1-2 years given the floor plan.
I hope I have roughly captured everything with some potential room for negotiation. I’ll leave out landscaping since that will be handled jointly with my parents and costs shared (hopefully).
Now I’m curious to hear your input (hope I’m not being too optimistic with these calculations, but better to fail early than too late). Thanks for your effort...
Best regards, doberman123
Sorry for spelling and grammar—too late and very tired, yawn...
Hello 6 Richtige,
thanks for your reply!
So, let’s take a look at what I’ve put together so far. I hope I haven’t made any major calculation errors, and I’ll just shoot from the hip...
Professional qualifications:
I am an electrician (currently working in switchgear construction). My brothers are a gas/water installer and a bricklayer by trade.
My experience with house construction is limited to working as an electrician on site and having installed roof tiles on three roofs... same goes for my brothers.
We have also helped build two more houses (for our parents) with the help of relatives, though we were still too young back then to do much besides roofing. At construction sites we usually work in groups of three to four (1-2 bricklayers and 2 laborers), and if more people need to be on site for a few days, I can arrange that.
Costs:
Interior walls + 1 outer shell with 700m² (7500 sq ft) of wall surface using KSS 3DF blocks—I don’t plan to lay them crosswise anymore because KSS has a high thermal conductivity, so I might add more insulation instead.
Cost for 3DF blocks: 1000 units cost €416, with about 30 blocks plus mortar per m², so the calculation is: 700*30/1000*416 = €8,763
For facing bricks / clinker bricks, I couldn’t find exact prices, so I’m estimating €30 per m², which makes 30*700 = €21,000
Mortar price per kilogram is €0.08 including VAT, needing 18kg for 1m², so 700*18*0.08 = €1,008
I simply doubled that considering the smaller facing bricks, so approximately €2,000
An integrated conservatory (sunroom) costs around €25,000
Stairs: €15,000
Interior finishing: €20,000
Windows & doors: €20,000
Roof: 350m² (3767 sq ft). I read somewhere that a pitched roof (30 degrees) costs between €75 and €100 per m². I’m going with €100 (not sure if this includes labor or if it’s accurate), so 350*100 = €35,000
Regarding insulation, I have read a lot—from “not worth it” to “absolutely necessary.” I have no idea which materials or construction substances last longer than 25 years. Some products have a stated lifespan of 25 years, which would be terrible if I had to remove the facing bricks after that period. It would definitely be better to have good insulation, especially since heating 280–300m² (3014–3229 sq ft) would get expensive over time.
That leads to the question of whether it’s worthwhile to insulate properly in order to get a better loan for insulation materials and heating systems. The more and cheaper the conditions, the better the cost-benefit ratio. So I’m also asking about available KfW housing standards—are there KfW 40 or 60 levels? What about KfW 55?
Well, I still need to research what kind of insulation and heating systems make sense—heat pumps, solar thermal, etc.
Still to determine are the material costs for:
Insulation of walls, slab, and roof?
Heating systems?
Concrete slab?
Foundation slab?
Right now, excluding insulation, heating systems, and electrical work, the total material cost is €146,736, which I think is quite generous for a house measuring 18m x 17m x 7m (59ft x 56ft x 23ft).
If these approximate numbers hold, that’s around €140,000 so far, as quantity discounts will likely apply.
The local development plan is “okay” according to the architect (said while drinking).
The house is similar to a prefabricated house but not even 50% identical—I mention this just so anyone curious can roughly imagine the floor plan.
Equity is between €30,000 and €40,000, plus land of approximately 1300–1600m² (14000–17200 sq ft).
Total material costs should not exceed €170,000, leaving about €20,000 to €30,000 for insulation, heating systems, electrical work, and concrete slab/foundation.
Total construction costs should be max around €200,000 to €220,000.
Construction time estimated at roughly 1-2 years given the floor plan.
I hope I have roughly captured everything with some potential room for negotiation. I’ll leave out landscaping since that will be handled jointly with my parents and costs shared (hopefully).
Now I’m curious to hear your input (hope I’m not being too optimistic with these calculations, but better to fail early than too late). Thanks for your effort...
Best regards, doberman123
Sorry for spelling and grammar—too late and very tired, yawn...
D
doberman12317 Feb 2010 14:54U-value Calculator
Can someone tell me what I need to enter there in order to calculate the insulation thickness?
Details:
Lime plaster: 15mm (0.6 inches)
Interior wall: lime sand hollow block 3 Df L/W/H in mm 240/175/113
Exterior wall: solid facing brick NF L/W/H in mm 240/115/75
Wall thickness without insulation: 305mm (12 inches)
Best regards, doberman123
Can someone tell me what I need to enter there in order to calculate the insulation thickness?
Details:
Lime plaster: 15mm (0.6 inches)
Interior wall: lime sand hollow block 3 Df L/W/H in mm 240/175/113
Exterior wall: solid facing brick NF L/W/H in mm 240/115/75
Wall thickness without insulation: 305mm (12 inches)
Best regards, doberman123
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