Foundations, raft or strip

Superdaddy

I am about to dig out my site to comply with my commencement notice. I had a lad pricing the job. Site is on a slight slope, it's a 140m2 footprint. I was just going to level the site and make the decision of foundation detail later, if anybody ever bothers to give me a bloody quote. But he pointed out to me that if I go for a strip foundation later I will need to bring in tons of fill to build it back up.
Passive raft foundations appeal to me. They appear a simplistic way to eliminate cold bridging.
People keep telling me strip foundations are cheaper. But why are they? Surely you use the same amount of insulation under the concrete to get the desired u value, same radon barrier. So what's left only concrete, steel and labour?
Has anybody been down this route. What is the price difference between raft and strip with comparable cold bridging detail and u value.

galwaytt

Superdaddy wrote: »

I am about to dig out my site to comply with my commencement notice. I had a lad pricing the job. Site is on a slight slope, it's a 140m2 footprint. I was just going to level the site and make the decision of foundation detail later, if anybody ever bothers to give me a bloody quote. But he pointed out to me that if I go for a strip foundation later I will need to bring in tons of fill to build it back up.
Passive raft foundations appeal to me. They appear a simplistic way to eliminate cold bridging.
People keep telling me strip foundations are cheaper. But why are they? Surely you use the same amount of insulation under the concrete to get the desired u value, same radon barrier. So what's left only concrete, steel and labour?
Has anybody been down this route. What is the price difference between raft and strip with comparable cold bridging detail and u value.

Raft, not even an uninsulated one is miles miles better. More accurate. Faster too.

Strip foundations are just not good enough imho.

A raft should be cheaper - especially in the West.
A passive raft is more than either.

4Sticks

Superdaddy wrote: »

I am about to dig out my site to comply with my commencement notice. I had a lad pricing the job. Site is on a slight slope, it's a 140m2 footprint. I was just going to level the site and make the decision of foundation detail later, if anybody ever bothers to give me a bloody quote.

Just continue as you startedyou will be fine

hexosan

Why are you making the decision on the foundation detail should this not be decided by your engineer.

Superdaddy

hexosan wrote: »

Why are you making the decision on the foundation detail should this not be decided by your engineer.

My engineer will tell me if it won't work or if it's outside regulations but at the end of the day it is my money so I will have make decisions.
I told him at the start I was looking at a raft along the lines of the ones detailed by viking and he said its a great job.
When someone gives me advice I take it and weigh it up. I had written off strip foundations but my digger men have made me revisit it.

4Sticks

Superdaddy wrote: »

My engineer will tell me if it won't work or if it's outside regulations but at the end of the day .... but my digger men have made me revisit it.

Lucky engineer

4Sticks

Superdaddy wrote: »

My engineer will tell me if it won't work or if it's outside regulations but at the end of the day it is my money so I will have make decisions.

SI 9 was just made for you

Superdaddy

4Sticks wrote: »

SI 9 was just made for you

I know what SI 9 is. Are you trying to be funny? Or do you think I should trust my money and home to other people without trying to understand it myself. Just leave the professionals to their job? See where that got us in the last 10 years.
I want to understand every aspect of my build. I want to check and double check everything these professionals tell me. If this is not the place to seek advice and share experiences then fine I'll go elsewhere.
I am new to this whole process and I am on a steep learning curve. It seems some people relish in showing others how wise they are by adding condescending one liners. If you are not going to be helpful don't bother replying.

Gambas

Superdaddy wrote: »

I know what SI 9 is. Are you trying to be funny? Or do you think I should trust my money and home to other people without trying to understand it myself. Just leave the professionals to their job? See where that got us in the last 10 years.
I want to understand every aspect of my build. I want to check and double check everything these professionals tell me. If this is not the place to seek advice and share experiences then fine I'll go elsewhere.
I am new to this whole process and I am on a steep learning curve. It seems some people relish in showing others how wise they are by adding condescending one liners. If you are not going to be helpful don't bother replying.

I like your approach. Building isn't that complicated if you are reasonably smart and you are determined to understand the concepts. You are 100% right not to 'leave it to the experts'. I've met more bluffers and guys that will choose the option that best suits them than I've met experts. Personally, I'd go for raft.

sydthebeat

Gambas wrote: »

I like your approach. Building isn't that complicated if you are reasonably smart and you are determined to understand the concepts. You are 100% right not to 'leave it to the experts'. I've met more bluffers and guys that will choose the option that best suits them than I've met experts. Personally, I'd go for raft.

famous last words......

4Sticks

Superdaddy wrote: »

I am new to this whole process and I am on a steep learning curve.

With a €300 set of working drawings.
You will learn a lot.

4Sticks

Gambas wrote: »

I'd go for raft.

Based on what information ? what are the pros and cons ?

Superdaddy

4Sticks wrote: »

Based on what information ? what are the pros and cons ?

You seem very knowledgable. Any chance of your views of raft and strip foundations as requested.

Gambas

4Sticks wrote: »

Based on what information ? what are the pros and cons ?

If you're going to quote, quote the full sentence. I said that it would be my personal choice - based on my experience as someone who has been in a similar situation to the op. Nothing more than that. I don't feel the need to justify my comment to you. I don't attach much weight to it, and the op is free to totally discard it.

I wouldn't dis the €300 drawings either -if you're going direct labour the tradesmen generally prefer verbal instruction in my experience. The OP will get there in the end and assuming he/she is prepared to put in the effort, and be well compensated financially for their approach.

4Sticks

Superdaddy wrote: »

You seem very knowledgable. Any chance of your views of raft and strip foundations as requested.

You clearly don't value expert advice or those who offer it.
So no. But don't worry the internet is HUGE.

BryanF

Superdaddy wrote: »

You seem very knowledgable. Any chance of your views of raft and strip foundations as requested.

Superdaddy, we appreciate your civil response

4Sticks wrote: »

You clearly don't value expert advice or those who offer it.
So no. But don't worry the internet is HUGE.

4sticks, if you don't want to help the poster try to pass over it.

Superdaddy,
We cant decide on your foundation here, as other have said its site specific and your eng needs to advise you
from the forum charter: Issues relating to the specification of structural components is prohibited. Any queries in this regard need to be dealt with by an architect/engineer privately.

antiskeptic

4Sticks wrote: »

With a €300 set of working drawings.
You will learn a lot.

4Sticks

Gambas wrote: »

-if you're going direct labour the tradesmen generally prefer verbal instruction in my experience

One of the biggest traps for the novice self builder that - trying to suit the workforce.

Superdaddy

4Sticks wrote: »

You clearly don't value expert advice or those who offer it.
So no. But don't worry the internet is HUGE.

Are you one of these "experts", did i miss some piece of expert advice in your posts while you were trying to ridicule me?
I have been called as a expert witness in cases over the years in my line of work. Its defined as a person that knows more than the average person on a given subject.
I have spoken to experts in many fields over the years. I have learnt that it is a very subjective thing. Many people claim to be experts, but experts don't know everything.

I would suggest that those who have completed what I am starting are experts, and possibly more expert than alot of so called professionals. It is those experts that i am targetting here for their views. Thanks to those who have given their views.

Superdaddy

BryanF wrote: »

Superdaddy,
We cant decide on your foundation here, as other have said its site specific and your eng needs to advise you
from the forum charter: Issues relating to the specification of structural components is prohibited. Any queries in this regard need to be dealt with by an architect/engineer privately.

Thanks Bryan,
My site can take either foundation. My questions are regarding the cost difference between the two. I am trying to get my head around why people are telling me the strip is so much cheaper. I am not asking which is structurally sound for my house.

sydthebeat

Superdaddy wrote: »

Thanks Bryan,
My site can take either foundation. My questions are regarding the cost difference between the two. I am trying to get my head around why people are telling me the strip is so much cheaper. I am not asking which is structurally sound for my house.

keep listening to your "digger guys"...... and the like of gambas... they will steer you straight :P

4Sticks

Superdaddy wrote: »

Are you one of these "experts", did i miss some piece of expert advice in your posts while you were trying to ridicule me?
I have been called as a expert witness in cases over the years in my line of work. Its defined as a person that knows more than the average person on a given subject.
I have spoken to experts in many fields over the years. I have learnt that it is a very subjective thing. Many people claim to be experts, but experts don't know everything.

I would suggest that those who have completed what I am starting are experts, and possibly more expert than alot of so called professionals. It is those experts that i am targetting here for their views. Thanks to those who have given their views.

We agree so. I can't help you - sorry.

Superdaddy

sydthebeat wrote: »

keep listening to your "digger guys"...... and the like of gambas... they will steer you straight :P

Am I to take this as sarcasm. You must obviously know these people well? How stupid of me to listen to two guys that have been digging out foundations for years and considering their views.
Is there anything else you wish to share? :rolleyes:
See what I did there..... I used an emoticon too.

Anybody else for a pop at a bit of sarcasm, ridicule or maybe even a constructive answer/ opinion as requested?

Gambas

4Sticks wrote: »

One of the biggest traps for the novice self builder that - trying to suit the workforce.

My boss issues verbal instructions. He'll be surprised when he finds out he's being doing my bidding for years. You just felt the need to come back with something belittling yet baseless. Says a lot really.

4Sticks

Your boss probably know what he's doing.

Stone Deaf 4evr

Superdaddy, I'm typing on my phone so I'll keep it short. The reason the strip should work out a lot cheaper is down to the volume of concrete and steel used. As a quick calc, measure the perimeter of your external walls, multiply that by 1 then that by 0.3. That'll give you a cubic metreamount for a 300mm thick strip.

Compare that with essentialy measuring your floor area and putting the same thickness under it. You'll also need to allow for a lot more steel.


Before anyone jumps in with corrections, these are purely for a rough outline of quantities.

Stone Deaf 4evr

Also, to whoever was sniping at the 400 euro set of working drawings, it's a house he's building, not a pharmaceutical factory. Any tradesmen worth their salt will know exactly what they're looking at. There a popular tendancy to paint tradesmen as fools or shysters, when in reality most of them have thousands of hours of hands on practical experience.

Pappacharlie

Just looking through the contributions here. You are dead right to try to get as much information from as many sources as possible. Be very careful of some of the advice given by some individuals here!
From my experience (building two houses) I would say that the raft is probably the best solution. The foundations is one area I would not skimp on! I would always trust the advise from an experienced builder if you know them well. They usually have forgotten more than most engineers know!!
Best of luck with the project.

Stone Deaf 4evr

Sorry, double post and touch won't let me delete.

4Sticks

Pappacharlie wrote: »

Be very careful of some of the advice given by some individuals here!

Yes- Be careful to only reinforce your prejudices.

sydthebeat

Stone Deaf 4evr wrote: »

Also, to whoever was sniping at the 400 euro set of working drawings, it's a house he's building, not a pharmaceutical factory. Any tradesmen worth their salt will know exactly what they're looking at. There a popular tendancy to paint tradesmen as fools or shysters, when in reality most of them have thousands of hours of hands on practical experience.

this forum is littered with thread on "who is responsible " when something goes wrong....

so go ahead an issue verbal instruction... pay cheap prices for professionals... and let your tradesmen do their own thing on site......

the disdain that house building (usually the single biggest finincial outlay of a persons life) is treated with by some people is simply flabbergasting

martinn123

Superdaddy wrote: »

I know what SI 9 is. Are you trying to be funny? .. If this is not the place to seek advice and share experiences then fine I'll go elsewhere.
I am new to this whole process and I am on a steep learning curve. It seems some people relish in showing others how wise they are by adding condescending one liners. If you are not going to be helpful don't bother replying.

While this Forum is Titled C&P, this thread shows the unfortunate habit of some, in denigrating those who seek information, for themselves, rather than handing over all decisions to a " Professional "
Snyde and synical posts, seeking to ridicule anyone, who might post a reasonable question, in what used to be a helpful and resourceful Forum, is now quite common,
I am also waiting for the obligatory "cartoon" to appear.

4Sticks

martinn123 wrote: »

While this Forum is Titled C&P, this thread shows the unfortunate habit of some, in denigrating those who seek information, for themselves, rather than handing over all decisions to hiring a " Professional ".

4Sticks

Superdaddy wrote: »

What is the price difference between raft and strip with comparable cold bridging detail and u value.

Off you go Martin123 - answer the reasonable question

martinn123

4Sticks wrote: »

Yep, a cartoon, just as I expected, [how tiring ] how many posts is that 4sticks in this thread, and not ONE, aiming to be helpful.

BryanF

Thread locked as its going nowhere