Pålning cost

[aksgir]

Hi,

I am trying to build a house in Stockholm (2 story, 180 m2, plus 30 m2 garage) and purchased a land. To make an idea for the cost estimation of complete project in turnkey project I went ahead for GeoTechnical which gave me surprise that the pålning will be required and which will increase the cost 400000 sek more (summary below).
Summa exploateringskostnad for me before this piling situation was 350,000 Kr which included platta (90 + 30 m2) on ground and cutting down and throw away of 10 trees.


"GRUNDLÄGGNING
All organisk jord samt eventuellt annat för grundläggningen otjänligt material avlägsnas varefter
vi rekommenderar att grundläggning utförs med pålar enligt BFS 2011:10, EKS 10,
Geoteknisk kategori 1. Dimensionering enligt § 15, tabell I-1.
Sonderingsstoppen får inte sättas lika med pålstopp, normalt tränger en påle djupare än
sondborren.

Geotextil skall utläggas som materialskiljande lager mellan schaktbotten och dränerande och
kapillärbrytande lager.
För schaktning i övrigt hänvisas till skriften ”Länshållning vid schaktningsarbete” SBEF,
Vägforskningsgruppen 1985 samt till Arbetarskyddsstyrelsens handbok H 13, ”Schaktning i
jord”.


and because of this suggestion I got below extra costs for the ground work.

The extra cost for work after the geo survey for reinforced plate, piling and extra gravel as needed. These costs can come and be adjusted after we have produced an exact pile plan so we know exactly how many piles are needed. Then the depth of the piles can also be changed depending on what the actual outcome is. But broadly speaking, this is what it will cost extra.

Totaly 385 533kr.

See the calculation below



Extra Uppackning för huset efter geoundersökning för pålning 220 ton uppskattat, 85250:-
Etablera pålning, 11500:-
Pålar, 27 st uppskattat, 18360:-
Pålmeter, 300m uppskattat, 144375:-
Förstärktplatta 130m2, 91000:-
Tomtplanering 4 m runt grund, överskottsmassor lämnas på hög.
Summa 350 485kr + UE påslag 10% (35 048kr) = 385 533kr

Now my question are these

1. Do you think this extra 385 533 Kr is a reasonable cost for pålning?
2. I signed the contract for the country last month and pretty sure there is no clause for renting find thing, so having paid around 300 000 kr for the country (10%) and rest needs to be paid next month when the country will be mine. Is it possible if I could cancel the deal for the tomt?

 

[Lärospånet]

Hello and welcome to the forum!

Why would you need piling? Who sold you the plot and is the plot in some kind of marsh land? How far to the nearest houses?

 

[aksgir]

Hi Lärospånet, Thanks. The plot was up for sale on Hemnet and the owner is a Old man. On the street except this tomt all plots already have houses.
I am not an expert here on Pålning but I am reading this forum since last month and found that most of the people get surprises with the budget when ground work is done so before I wanted to sign the contract with the housing company, they suggested to do the geotechnical survey to be sure about the estimation to as close as possible. I also thought it was a good idea before I sign contract with them to go for that. In the survey the company found that the sand is wet and Mountain is 10-12 meter below the land.

JORDLAGERFÖLJD.
Jorden i de undersökta borrpunkterna består lös till mycket lös lera av lös till mycket lös lera
innan stopp för berg eller block vid 9,5 till 11 meters djup.
Redovisade sonderingsstopp anger stopp med hänsyn tagen till respektive sonderingsmetod.

and then after the survey result the housing company sent the report to their ground work contractor for the extra cost and he said 400 000 Kr will be extra for the ground work due to this pålning as I explained in the previous post.

I am not sure if it will really cost that much so thats why I wanted to get some help from this forum.

 

[patrikd84]

Is the soil that poor? Think its pretty rare that you pile a small house slab but if the soil is that bad maybe the earth pressure get too high ...

Price depend on what pile is used, concrete or steel (wood dont seem feasible here), but unfortunently I never prescribed as small piles that probably will be used here (guessing small steel piles, RR75) so dont have a sense of the price - however price per meter installed pile is about 580 kr with all pile-related costs included which is around the same as an estimated price for a square 350 mm concrete pile.

The prices I have are for larger projects though, so its not really easy to compare directly. More piles that are shallow cost more than few and long aswell.

 

[patrikd84]

Hi Lärospånet, Thanks. The plot was up for sale on Hemnet and the owner is a Old man. On the street except this tomt all plots already have houses.
I am not an expert here on Pålning but I am reading this forum since last month and found that most of the people get surprises with the budget when ground work is done so before I wanted to sign the contract with the housing company, they suggested to do the geotechnical survey to be sure about the estimation to as close as possible. I also thought it was a good idea before I sign contract with them to go for that. In the survey the company found that the sand is wet and Mountain is 10-12 meter below the land.

JORDLAGERFÖLJD.
Jorden i de undersökta borrpunkterna består lös till mycket lös lera av lös till mycket lös lera
innan stopp för berg eller block vid 9,5 till 11 meters djup.
Redovisade sonderingsstopp anger stopp med hänsyn tagen till respektive sonderingsmetod.

and then after the survey result the housing company sent the report to their ground work contractor for the extra cost and he said 400 000 Kr will be extra for the ground work due to this pålning as I explained in the previous post.

I am not sure if it will really cost that much so thats why I wanted to get some help from this forum.

Does the report say anything about

• allowed earth pressures?
• ongoing settlements in the area?
• how the foundation of the surrounding houses are constructed?

 

[Lärospånet]

I'm in lurker mode just observing and learning as patrikd84 knows this stuff!

 

[patrikd84]

I'm in lurker mode just observing and learning as patrikd84 knows this stuff!

Feeling the pressure now

 

[Noseone]

In my area in Järfälla, all houses stands on poles. Old sea bottom.

 

[aksgir]

Does the report say anything about

• allowed earth pressures?
• ongoing settlements in the area?
• how the foundation of the surrounding houses are constructed?

This is what Report says

AVVÄGNING
Ingen avvägning är utförd.

JORDLAGERFÖLJD.
Jorden i de undersökta borrpunkterna består lös till mycket lös lera av lös till mycket lös lera
innan stopp för berg eller block vid 9,5 till 11 meters djup.
Redovisade sonderingsstopp anger stopp med hänsyn tagen till respektive sonderingsmetod.

GRUNDVATTEN.
Grundvattensituationen har inte undersökt.

STABILITET.
Onormala stabilitetsproblem i samband med planerade byggnader bedöms inte vara aktuellt.

SÄTTNINGAR.
Lös lera är sättningskänsligt för lastökningar. För normalkonsoliderad lera innebär en lastökning
med 10 kPa att konsolideringssättningar inträffar med ca 3-5 cm per meter lös lera.

GRUNDLÄGGNING
All organisk jord samt eventuellt annat för grundläggningen otjänligt material avlägsnas varefter
vi rekommenderar att grundläggning utförs med pålar enligt BFS 2011:10, EKS 10,
Geoteknisk kategori 1. Dimensionering enligt § 15, tabell I-1.
Sonderingsstoppen får inte sättas lika med pålstopp, normalt tränger en påle djupare än
sondborren.

Geotextil skall utläggas som materialskiljande lager mellan schaktbotten och dränerande och
kapillärbrytande lager.
För schaktning i övrigt hänvisas till skriften ”Länshållning vid schaktningsarbete” SBEF,
Vägforskningsgruppen 1985 samt till Arbetarskyddsstyrelsens handbok H 13, ”Schaktning i
jord”.

 

[patrikd84]

JORDLAGERFÖLJD.
Jorden i de undersökta borrpunkterna består lös till mycket lös lera av lös till mycket lös lera
innan stopp för berg eller block vid 9,5 till 11 meters djup.
Redovisade sonderingsstopp anger stopp med hänsyn tagen till respektive sonderingsmetod.

Going abit off topic (since you asked regarding price) but here goes:

Did they actially do drillings? Normally you get a list and depth for each soil layer and you should also have a dry crust of clay above the goundwater level, otherwise the grass would sit in some wet clay - and the picture suggests otherwise.

SÄTTNINGAR.
Lös lera är sättningskänsligt för lastökningar. För normalkonsoliderad lera innebär en lastökning
med 10 kPa att konsolideringssättningar inträffar med ca 3-5 cm per meter lös lera.

GRUNDLÄGGNING
All organisk jord samt eventuellt annat för grundläggningen otjänligt material avlägsnas varefter
vi rekommenderar att grundläggning utförs med pålar enligt BFS 2011:10, EKS 10,
Geoteknisk kategori 1. Dimensionering enligt § 15, tabell I-1.
Sonderingsstoppen får inte sättas lika med pålstopp, normalt tränger en påle djupare än
sondborren.

Geotextil skall utläggas som materialskiljande lager mellan schaktbotten och dränerande och
kapillärbrytande lager.
För schaktning i övrigt hänvisas till skriften ”Länshållning vid schaktningsarbete” SBEF,
Vägforskningsgruppen 1985 samt till Arbetarskyddsstyrelsens handbok H 13, ”Schaktning i
jord”.

Seems reasonable with a piled foundation with those settlements per meter at least, since only the concrete slab would give you pretty large settlements - assuming 200 mm thickness resulting in at least 10 cm over time (probably more).

One issue I’d look up before going any further is how the other houses look and if they have issues with settlements. For instance, if the garage is piled but the parking space in front is not, you may get problems with an edge later on - same goes for the house if you add more load you may need to add steps to get into your house.

Since a more detailed geotechnical survey probably is too expensive (testing clay in lab) I would talk to the neighbours to get a sence of the settlement issue as this is good to think of early in the building process.

 

[bossespecial]

Piling of houses is are very common and based on the geotechnical survey there is ni question about it. As mentioned they use steel piles, commonly used dimension RR/RD75 and 115. RR and RD stands for the way it is installed.
As mentioned, when you pile a building, the surraounding soil will settle. I dont know if you understand swedish but here is a document how to build on clay https://www.omboende.se/Global/Bygga/Dokument/sattningar_i_smahus.pdf

When i look at the costs they are very similar to a friend of mine concerning the piles and the thicker slab. Why you need so much extra groundwoork just for piling is a questionmark for me...

 

[patrikd84]

Piling of houses is are very common

Good to know! Didnt think it was common for small slabs like this.

 

[aksgir]

Asked the neighbors and nobody had to do any pålning and their houses are also quite stable as they told me.
So either I am so unlucky or they are trying to fool me to earn some extra.

 

[patrikd84]

Asked the neighbors and nobody had to do any pålning and their houses are also quite stable as they told me.
So either I am so unlucky or they are trying to fool me to earn some extra.

Hmm, do you have rock above the surface anywhere near the site or at your neighbours? Would be very odd if the clay is so much worse just meters away.

How was the survey conducted? Did they have a drilling rig on site? Took any samples? Basically, what is the report based on? Actual findings or some ”geo map” of the area?

Had the neighbors done any surveys before their houses went up?

 

[aksgir]

Hmm, do you have rock above the surface anywhere near the site or at your neighbours? Would be very odd if the clay is so much worse just meters away.

How was the survey conducted? Did they have a drilling rig on site? Took any samples? Basically, what is the report based on? Actual findings or some ”geo map” of the area?

Had the neighbors done any surveys before their houses went up?

Yes just across the street there is a mountain. I can see a little rock in the middle of my tomt also but not sure if thats part of a mountain or is just a rock.

Survey was done with a machine and the guy had computer on his machine to do some sort of geo measurements and he said they dont need to take any clay to send it to lab. Since their system measures everything while drilling in.

Neighbors did do geotechnical and didn't find any problems with the soil.