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Durisol ICF: tying in the first to subsequent pours: which resin?


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Just a quick question.

Which resin (brand-names please) are suitable for embedding rebar into existing concrete to make it ready to tie into subsequent pours? I have looked at the technical guidance for that in the Durisol technical information, and can't find it. 

 

With a bit of luck, we might  be completing this phase of the build within a few days.

Fingers and toes crossed.

Ian 

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I'm using Fisher FIS VT to embed threaded rods into the Icf core for a steel beam - not sure if it's also suitable for rebar. It can be applied in wet conditions which might prove useful. 

 

In terms of the need to tie in pours (and lack of Durisol  guidance) , I wasn't aware this was a general requirement unless a retaining wall in which case rebar will already be cast in? Is it a retaining wall or an S. E requirement to do this? 

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Ah well - moving on swiftly! I went with a mix on application method rather than glass capsules. You need a special applicator gun - standard one won't do I'm afraid. I've not done it yet,  it's on my endless list of tasks! 

 

http://www.screwfix.com/p/fischer-fis-vt-vt-vinylester-chemical-mortar-resin-380ml/14364

 

http://www.screwfix.com/p/rawlplug-rawlplug-resin-gun/30939

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Any reason not to cast in the connecting rebar?

 

It seems to be a lot of work to go around drilling and resin bonding rebar in after a pour.  Our retaining wall is made from doubled up 215 hollow blocks, with rebar and concrete infill, so similar to Durisol in terms of the basic principle.  The rebar was just left poking out after each pour.

Edited by JSHarris
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5 minutes ago, JSHarris said:

Any reason not to cast in the connecting rebar?

 

It seems to be a lot of work to go around drilling and resin bonding rebar in after a pour.  Our retaining wall is made from doubled up 215 hollow blocks, with rebar and concrete infill, so similar to Durisol in terms of the basic principle.  The rebar was just left poking out after each pour.

Don't labour l what I think is a sore point!  ;-) 

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7 minutes ago, JSHarris said:

Any reason not to cast in the connecting rebar?

 

It seems to be a lot of work to go around drilling and resin bonding rebar in after a pour.  Our retaining wall is made from doubled up 215 hollow blocks, with rebar and concrete infill, so similar to Durisol in terms of the basic principle.  The rebar was just left poking out after each pour.

 

Right, I'll go and take a photo of it: worth a thousand words and all that.

 

2 minutes ago, jamiehamy said:

Don't labour l what I think is a sore point!  ;-) 

 

There is a point in sore points. Learning. And in my case hand over fist. Not before time either.

Ian

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I had to pour my garage footings in stages and just pushed 3 x12mm x 700mm rebar into the soil wall at the bottom of the trench to be filled with concrete, leaving tails 350mm long sticking out which where covered in concrete. Then when I dug out the next section to be poured and thus joining the two sections together I had 3 x 12mm re-bar, 350mm long tails sticking out which then joined the two sections together.

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Ok if this is a replacement for a cast in there is only one adhesive I would trust and that's a Hilti HY200 - it's what it is designed to do. 

 

https://www.hilti.co.uk/anchor-systems/injectable-adhesive-anchors/r4803

 

Hilti tech services are superb - give them a call and explain what you need and they will advise what is the best adhesive as you may be able to get away with a lower spec if the loading is shear rather than axial. 

 

Downside is this stuff isn't cheap and needs a Hilti injector gun to install but it won't go anywhere for a long time ..! It's what they use to fix crash barriers onto Motorway bridges ....

 

 

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This is what we've got: 

20170807_085403.thumb.jpg.7fcc0e9251359cff6bf6101a7dd589e5.jpg

 

The insulation is 'backed up' as it were by the concrete-filled holes. Tanners suggested every fourth hole ought to have a bit of rebar sticking up, ie. one piece of rebar in every other block. The bit of rebar you can see is the one strengthening the soldier course at head of a window.

 

This section of the build only needs one more full course (plus a bit) to sit on the top of the existing blocks. So, not much needed here, but it needs to be 'reet' as thyey say up here.

Ian

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Hmm,  surely you just need to pop in some dowels into a slightly oversize hole? Resin fastening rebar is not only time consuming but is not offering anything here - apart from costing a lot. Still baffled as to why they didn't just finish the wall before pouring but you are where you are. 

 

That piece of half cast rebar annoys me - what poor workmanship - it's essentially a lintel that has being cast in two parts. I would absolutely put a fresh length over that on a concrete chair or something and cast it anew. As for resin fastening rebar - its your money but if that's what the S. E demands,  fair enough but if not,  dowels are what should be needed if you want peace of mind. The cement in the concrete will embed it and do the job as it would in any other area - resin not required. 

 

 

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Another + for Fisher:

 

This is used for anchoring safety harness eyebolts etc, Fischer FIS V 360S. It's brilliant stuff. They do a rebar specific one...not sure this is it though:

 

20170807_085727.thumb.jpg.52f069f57996ef5c14a8c5a0dba25313.jpg

 

It is two pack as in resin & hardener in separate, piggy backed tubes. Far superior than the stuff that "fits in a normal mastic gun". It takes a special gun. This is the plastic one, they also do a metal version:

 

20170807_093154.thumb.jpg.6ede362ce531a3af07c204a54a9d69a9.jpg

 

Tbh I have of late used the DeWalt "standard mastic gun" one for some non critical stuff and it was OK but not Fischer grade to my mind.

 

I got given a couple of slightly out of date Fischer tubes that couldn't be used along with the gun and have used the system to fit M10 studs for supporting some of the heavier timber stud sections in the bathroom, the wc frame etc. Since been buying the resin, not cheap!

 

You MUST get the proper puffer to blow the holes out after drilling. A vac with bit of thin tube is no good nor is a compressor. Each are better than nothing but they only blow/suck in one direction so force loose debris into the sides of the drilled hole. A manual puffer sucks and blows on alternate strokes and really dislodges crap & clears things out. I've tried a Henry and a compressor then the proper tool and more dust always comes out.

 

Before Fischer we used Rawlplug R-Kem.  (Their tech support was great).

 

Both systems take special guns. 

 

In a previous life way back I used to use Hilti stuff and again special guns required. Think I've still got a couple up the shed people are welcome to if any use. Though I suspect the systems have moved on after 20/30 years and the guns are obsolete. Funny feeling I binned them of late during the Great Clear Out of 2017 which appears to have achieved precisely nothing in terms of "getting tidy"! :)

 

 

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46 minutes ago, jamiehamy said:

Hmm,  surely you just need to pop in some dowels into a slightly oversize hole? Resin fastening rebar is not only time consuming but is not offering anything here - apart from costing a lot. Still baffled as to why they didn't just finish the wall before pouring but you are where you are. 

 

That piece of half cast rebar annoys me - what poor workmanship - it's essentially a lintel that has being cast in two parts. I would absolutely put a fresh length over that on a concrete chair or something and cast it anew. As for resin fastening rebar - its your money but if that's what the S. E demands,  fair enough but if not,  dowels are what should be needed if you want peace of mind. The cement in the concrete will embed it and do the job as it would in any other area - resin not required. 

 

 

 

Tell me more, please!

  • Dowels: pieces of rebar cut to short lengths and popped in the holes?
  • Workmanship: thanks so much for pointing that out: I thought it was OK. But thinking about it using your comment as a starting point , that's very helpful.
  • Whassa 'concrete chair'?
  • '... dowels are what should be needed if you want peace of mind...' yessir 's whar I want what I really really want. Give us a hint of how to sort it, please!
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45 minutes ago, Onoff said:

Another + for Fisher:

[...]

This is used for anchoring safety harness eyebolts etc, Fischer FIS V 360S. It's brilliant stuff. They do a rebar specific one...not sure this is it though:

[...]

You MUST get the proper puffer to blow the holes out after drilling.

 

 

The only puffer I know is the fish that stings like mad if you touch it and a lens puffer. Enlighten my darkness, I beseech you. Please

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So let's start with the problem statement-

 

You are casting a concrete wall in two pours. You want to join the two sections to ensure no horizontal movement? 

 

Solutions-

 

1 - drill and then resin bond pieces of steel reinforcing bar vertically on the top of the first poured course to be covered with the final pour thus providing the horizontal interlock. Given that the rebar is in a vertical hole it can't move horizontally anyway so not clear on resin benefit here. 

 

2 - drill an oversize hole,  say 20mm wide and 300mm deep. Pop a 12mm x 600mm piece of rebar in prior to pour. Pour concrete and gentle vibrate to ensure concrete gets down the hole and once concrete has gone off you have an interlock. Ensure at least 40mm concrete cover of the rebar all round. 

 

3 - do nothing. Between the top of the first pour not being smoothed(which is fine)  and the holes in the tops of the icf,  you have a very good key already there and once you pour the concrete there is not going to be any horizontal movement anyway. 

 

If you chose to recast the lintel,  you need to place a new piece of horizontal rebar - you can sit this on a piece of concrete at either end,  can really be any old piece,  although when laying founds you can buy chairs for this which mean they become a part of the founds/slab that are the same material unlike say a wooden chair which might deteriorate and cause a weakness. 

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At last, someone who is clear about the need for concise problem statements. What a relief.

 

I'm going for 2 and 3, as well as a bit of the addendum. And I'm going for @Onoff's puffer and @PeterW's Hilti '...solution....' (Christ how I HATE the abuse of that innocent little word).

I'm going to trial the use of resin because I'm going to need to fix the first floor POSIs, and they need to be 'resined' in. And for that I need clean holes.

 

================================

Monday morning: HERAS unlocked, 0700. PC's arriving today. Cos He Told Me

 

0900, a quick polite text to the PC: 

 

'You coming today?

'I'm going to be with you erm, ahhhh, mid-week, Ian'

'And you knew that you were going to be delayed yet again by Wednesday of last week didn't you?'

'Er, well, yes'

 

If you can't take a joke, don't self-build

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Hi Ian.

 

You won't want to hear this, and it may not be a problem, but in case it has not been addressed there is also a toppling force on the wall which needs to be 'managed' which may or may not be why the pull out resistance of the rebar needs to be good and the number of them high enough. As depending upon how high the next pour is you will have a weak line along the join which could, in some weather conditions, put pressure on the top of the wall and cause a failure. If there are corners in the pour or a good number of castelations (you picture shows a few) the risk is lessened.

 

Sorry!

 

 

Wall.png

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Hi Mike. I try to encourage people to tell it like it is when appropriate, and here, it is.

 

The wall in the photo above needs one more course and a fiddly bit (some insulation to prevent cold bridging). The wind force needed to topple that would have  to be high indeed.

Thanks anyway.

Ian

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