When is concrete too hard??

5936 Views 14 Replies 9 Participants Last post by Guywithskills, Jan 5, 2013

forcedreno2012

Discussion Starter · Dec 29, 2012

This may seem like a really silly issue but here goes.

With the rebuild we built a walk in closet and extended out the footprint of the master bath for future improvement. While doing this I saw something that I have never seen before on any remodelling project and even the he man was stumped. When nailing in the bottom plate we could only get about one out of 3 of the nails to go through. The rest would curl under and not even scratch the concrete.

I'm going to butcher this but we were using the tool that takes bullets and essentially shoots the nail through the bottom plate and into the concrete. No idea what it is called but in our house it hates me - the one tool I is askeerd of.

We were using PT bottom plate. We even ran out of bullets for about 20 feet of bottom plate. (Insert Elmer Fudd joke here " No more buwetts??):laughing: so went and got some more.

I am now half deaf and hoping I will not set off the airport sniffers this week when I travel because of the residue.

Is this the norm or do we just have REALLY hard concrete? The slab was poured in 93 and I am a little nervous because we have not even started on the kitchen etc and wondering if we are going to have the same issues. Kinda concerned for the rest of the stuff we have to do.

Do I need to get bigger "buwetts" or are we doing something wrong. Is it because its colder now? We are in Mississippi so not frosty or snowy or anything like that but its a bit chilly. Should we not be using PT for the bottom plate?

Thanks in advance

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stadry

· #2 · Dec 29, 2012

1st, were you using a strong enough load for the gun ? if you got enough penetration for some, its possible the conc was more heavily mixed w/extremely hard coarse aggregate but unlikely,,, p/t is the correct mtl for a btm plate on conc,,, the reason to 'shoot' the plate is to allow it to resist lateral force/load as gravity keeps it where it is placed,,i'm not aware any rqmt that so many devices per foot be installed,,, you could use a hammer drill & insert sinusoidal anchors or lead-shield ( drop-in's ) anchors in place of shot nails.

we're presently partitioning off bsmt furnaces & creating exercise room - 20' has 5 anchors,,, doubtful your temps are much lower than ours in atl - just hold the tight against the btm plate ( probably redundant - most don't 'fire' until the safety is depressed )

hand drive

· #3 · Dec 29, 2012

better to hammer drill and install anchors. the shots and pins will bend instead of penetrating the concrete a lot of times and some concrete is harder than others.

joecaption

· #4 · Dec 29, 2012

Use PL adhesive and 3" Tap Cons.

Daniel Holzman

· #5 · Dec 29, 2012

You were probably using a Ramset. There are a variety of load types, pins (not called bullets), and caliber available, depending on the hardness of concrete, and the pin diameter and depth of penetration required. When I did this work, we had .22 and .38 caliber shot available, in power ranging from light load to extra heavy load, I can't remember the colors. You most likely had too light a shot. And by the way, that hearing loss is probably permanent, best to use industrial class ear protection and a face mask to minimize potential for eye injury.

concretemasonry

· #6 · Dec 29, 2012

You do not need much to hold the studs for a closet in place because friction, intersecting walls and even possible load being picked up by other parts of the home.

All you are trying to do is prevent the plates from moving horizontally and are not building the Titanic. Extra fasteners are a waste of time, money and unnecessarily make things more complicated. There is no need to drive the nails to the level of the top of the plate.

Dick

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forcedreno2012

Discussion Starter · #7 · Dec 29, 2012

Thanks to all. I will ask the hubbyabout the shot load. I think we were using .22's.

Thanks for giving the name of the ramset I always forget that one for some reason. As for the hearing loss, we do use the correct safetly gear I am a nit in that respect and after about half an hour things were back to normal...well as back to normal as can be. The hubby is convinced I have selective hearing anyway.

epson

· #8 · Dec 29, 2012

you can read up here: http://www.ramset.com/fasteners.asp

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forcedreno2012

Discussion Starter · #9 · Dec 30, 2012

Thanks Epson great article. Will review with the other half. I know we were using the correct fastners and load based on what I read so we may need to change to a higher caliber for want of a better word.

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stadry

· #10 · Dec 30, 2012

you can't change the caliber unless you get a different gun but .22's fine - you CAN change the force ( 'hotness' ) - green, red, yellow, brown iirc

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hand drive

· #11 · Dec 30, 2012

forcedreno2012 said:
Thanks Epson great article. Will review with the other half. I know we were using the correct fastners and load based on what I read so we may need to change to a higher caliber for want of a better word.

chances are a higher caliber will only cause the pin to bend at a quicker rate as you shoot it in because of the hard concrete. As Joe mentioned, the easiest is probably construction glue and 3" tap con screws. construction glue can be used along with or even replace nails in lots of applications...

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forcedreno2012

Discussion Starter · #12 · Dec 30, 2012

Are you all in cahoots or what?? I was just getting the "well, we need to get a bigger ramset anyway" discussion and here you are all agreeing with him lol.

Mr "two tools for every job and the two tools do not necessarily have to relate to the job at hand" :whistling2:

We did use glue under the bottom plate in all the past applications - he has always done it. I know we were using the yellows. I do know if he gets a bigger one - imma outta here when he uses it :laughing:

Thanks for all the information, we are a about a month away from the front half of the house so have some time to try some different applications.

funfool

· #13 · Dec 30, 2012

I bet your ramset is fine, for a new tool I would get a hammer drill.
If these were load bearing walls, would drill and insert molly bolts to hold them in place.

For your closet walls, I would apply liquid nails to the plate, drill a 1/4" hole through the plate into concrete.
Use 2, 16 penny nails and drive them in the hole together. This creates such a wedge and really holds well. I have used it for applying sleepers to concrete before insulation and sub floor.

First time I was showed this trick, was just for a temporary office in a garage.
Went back 3 months later to remove the walls, I needed my 3' crow bar to pry the plates up, and it was leaving wood on the floor where glue was applied.

I do not own a ramset, When I worked union carpenter ... we used them to attach metal track to floor for metal studs.
Is a big difference in thickness between a wood 2x4 and a metal track.
I just do not think you get enough holding power from them with wood.
Is why I do not own or need one, but company I work for does have one ... use it 3 or 4 times in 8 years ... I would not want 2 of them.

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hand drive

· #14 · Jan 1, 2013

funfool said:
I bet your ramset is fine, for a new tool I would get a hammer drill.
If these were load bearing walls, would drill and insert molly bolts to hold them in place.

For your closet walls, I would apply liquid nails to the plate, drill a 1/4" hole through the plate into concrete.
Use 2, 16 penny nails and drive them in the hole together. This creates such a wedge and really holds well. I have used it for applying sleepers to concrete before insulation and sub floor.

First time I was showed this trick, was just for a temporary office in a garage.
Went back 3 months later to remove the walls, I needed my 3' crow bar to pry the plates up, and it was leaving wood on the floor where glue was applied.

I do not own a ramset, When I worked union carpenter ... we used them to attach metal track to floor for metal studs.
Is a big difference in thickness between a wood 2x4 and a metal track.
I just do not think you get enough holding power from them with wood.
Is why I do not own or need one, but company I work for does have one ... use it 3 or 4 times in 8 years ... I would not want 2 of them.

pins for the metal are really short and effective when compared to pins for wood no doubt. shooting track with short pins into steel is fun stuff and LOUD!

Guywithskills

· #15 · Jan 5, 2013

For a closet, I would use construction adhesive, glue the plate down and then driven Hard Case Concrete Nails. One between each stud and hold back min 4" from end of plate to avoid splitting wood. Maybe 2" or 2 1/2" long, longer are more prone to bend. I use a 3lb sledge hammer and stop beating when it even starts to bend. You are just putting a few pins in to stop it from moving laterally as previously stated. It is a non-bearing wall. I would do this even on a internal bearing wall. Exterior bearing wall requires more. there is no benefit than doing more than needed. This is mostly for when carpet is placed and they push on the walls. It really doesnt take that much.
If your curious, concrete continues to cure over the years, it gets harder every year. I did a job on an Air Force base on the flight deck. The concrete was 12" thick, bomb hardened, poured before WWII, it was a fighter training base. We had to saw cut 5ft squares, we tried to jack hammer them out with a 110lb jack hammer. With new points, the jack hammer left minimal denting even. You can hit your drive with a blunt hammer and it will dent it. We ended up using a mining star drill and drilled the 5ft squares and lifted them out and hauled to the dump in square form. We were grateful to get it out. We were putting in a storm drain where the water would get 8" deep in the rain.

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