Beam & Block Overkill?

[scottishjohn]

1 minute ago, JSHarris said:

 

Yes, as I wrote, they fit a Radon barrier and sump as standard when installing a slab in a Radon area.

don,t think i ever seen that up here and we have loads of granite

just slab

or is this with suspended floor ? to vent under the floor above the slab

[Declan52]

11 minutes ago, scottishjohn said:

is there not a radon barrier material you can fit under slab?

I just swapped out the dpc that I put on top of my hardcore with a radon barrier type. It's lapped up onto the top of the founds so your first course is built on top which means it's sealed. 

[Jeremy Harris]

16 minutes ago, scottishjohn said:

don,t think i ever seen that up here and we have loads of granite

just slab

or is this with suspended floor ? to vent under the floor above the slab

 

It's a standard detail for the Kore passive slab, and any other I'd have thought.  Here's the Kore info on their range of passive slabs; all include a Radon barrier as standard; it's shown in every section drawing:

 

KORE-Passive-Slab-Design-Guide.pdf

[epsilonGreedy]

1 hour ago, andy said:

cutting our loses with SE.

 

 

You should not have to seek advice on an internet forum to comprehend the design intentions of your highly paid professional. Phone him up, tell him you are not satisfied with his abnormal design presented so far and demand a substantial 1 on 1 meeting.

 

Your current confusion with your interim classic foundation plan need not motivate a complete u-turn in foundation methodology.

 

What are the credentials/experience of your SE?

[epsilonGreedy]

12 hours ago, Simplysimon said:

just done my b&b floor, wouldn't do it again. expensive and quite a bit of deflection, live and learn.

 

 

Where did the expense creep in? I thought one advantage of traditional/mainstream building methods is they are cheaper in the first instance though with the longer term cost of less insulation.

[scottishjohn]

13 hours ago, Simplysimon said:

just done my b&b floor, wouldn't do it again. expensive and quite a bit of deflection, live and learn.

deflection ?

do you mean it bounces or it is sagging  in middle ,or up in the middle?

sounds like someone has not done the sums and got correct beams ,should none of that 

[Simplysimon]

1 hour ago, epsilonGreedy said:

 

Where did the expense creep in? I thought one advantage of traditional/mainstream building methods is they are cheaper in the first instance though with the longer term cost of less insulation.

the cost of the beams, doubled up on one section due to span and then the time to fit the blocks, then all the cuts. had we known, the single leaf mid span walls would have been doubled to allow the beams to run continuously rather than side by side which contributed to a lot of cut blocks to fill the holes. it would have been cheaper to build a double wall. a dwarf wall to cut the span would also have negated the doubling up and would probably been cheaper

 

15 minutes ago, scottishjohn said:

deflection ?

do you mean it bounces or it is sagging  in middle ,or up in the middle?

sounds like someone has not done the sums and got correct beams ,should none of that 

it bounces slightly, was more apparent on the wide span with doubled beams but has since firmed up since the thin (25mm) screed. it is the smaller section which is still deflecting slightly. BTW specced correctly.

[scottishjohn]

2 minutes ago, Simplysimon said:

it bounces slightly, was more apparent on the wide span with doubled beams but has since firmed up since the thin (25mm) screed. it is the smaller section which is still deflecting slightly. BTW specced correctly.

If you say so 

 

 

[Vijay]

20 minutes ago, Simplysimon said:

the cost of the beams, doubled up on one section due to span and then the time to fit the blocks, then all the cuts. had we known, the single leaf mid span walls would have been doubled to allow the beams to run continuously rather than side by side which contributed to a lot of cut blocks to fill the holes. it would have been cheaper to build a double wall. a dwarf wall to cut the span would also have negated the doubling up and would probably been cheaper

 

it bounces slightly, was more apparent on the wide span with doubled beams but has since firmed up since the thin (25mm) screed. it is the smaller section which is still deflecting slightly. BTW specced correctly.

what was the beam spec? I beefed mine up as much as I could for the worry of that

[epsilonGreedy]

11 minutes ago, Simplysimon said:

the cost of the beams, doubled up on one section due to span and then the time to fit the blocks, then all the cuts. had we known, the single leaf mid span walls would have been doubled to allow the beams to run continuously rather than side by side which contributed to a lot of cut blocks to fill the holes. it would have been cheaper to build a double wall. a dwarf wall to cut the span would also have negated the doubling up and would probably been cheaper

 

 

I decided to add a dwarf wall where the official foundation plan showed beams spanning a 5.7m x 6.5m square. I marked it up with the digger chap literally 5 minutes before he dug the dwarf wall trench. The motivation for this last minute change of plan was that the evening before my pro self build neighbour strolled over to look at my marking up and he advised against trying to handle 5.7m beams plus he mentioned the bounce issue.

 

I wonder why the pro's who design foundations don't volunteer these options when dealing with self builders.

[Simplysimon]

46 minutes ago, Vijay said:

what was the beam spec? I beefed mine up as much as I could for the worry of that

span 6.4 doubled up t42, span of 4.2  t42 single, it's the single with the small span which is now deflecting. will probably be fine when loaded with studs etc.

[PeterW]

1 hour ago, epsilonGreedy said:

 

I wonder why the pro's who design foundations don't volunteer these options when dealing with self builders.

 

Because it’s not in the spec. And a lot of these companies doing this are in it to a price - TW etc don’t double up “because it feels stiffer”, they do it to keep inside the spec which will be Xmm deflection over Ymm span. 

 

If you want less deflection than industry tolerance then you have to specify it ...

 

It’s used by mainstream builders as it can be installed by a pair of grunts who share a brain cell on Tuesdays .. Quick and easy when you have gangs doing it all day and the tolerances are “adjusted or hidden” using the brushed in screed. 

[Mr Punter]

For timber , concrete and steel beams or joists on a residential project, 4m spans are fairly economical. Much more and it is worth looking at additional midway support.

[epsilonGreedy]

44 minutes ago, PeterW said:

Because it’s not in the spec. And a lot of these companies doing this are in it to a price - TW etc don’t double up “because it feels stiffer”, they do it to keep inside the spec which will be Xmm deflection over Ymm span. 

 

If you want less deflection than industry tolerance then you have to specify it ...

 

 

Yes fair point, my foundations were dug from the diagrams produced by the architectural technician which included his guess re. the ground floor beam layout. Somewhere in the small print there was a getout clause about the final beam spec to be produced by a specialist supplier, so I suppose I was not paying him to enter into a protracted discussion re. floor structure. 

[andy]

On 19/04/2019 at 10:41, epsilonGreedy said:

 

You should not have to seek advice on an internet forum to comprehend the design intentions of your highly paid professional. Phone him up, tell him you are not satisfied with his abnormal design presented so far and demand a substantial 1 on 1 meeting.

 

Your current confusion with your interim classic foundation plan need not motivate a complete u-turn in foundation methodology.

 

What are the credentials/experience of your SE?

 

What I was after (and usefully acquired, many thanks all!) is confirmation if the foundation design is "normal" as I am no expert in these things.

 

As you rightly say, I am paying someone a lot of money who is supposed to be and I will be having a meeting with them ASAP to tell them to design what I want.  This nonsense design only came in at the end of Thursday, so not had any time to liaise with them yet.  It is also the first time that it had ever been mooted that such insulation penetrating walls were in the design at all, so we're pretty unimpressed right now.