Concrete masonry piers with no mortar in bed joints

[ajk1]

The attached photo shows a newly constructed cottage that is supported on concrete block piers that appear to have been laid with no mortar in the bed joints. Is that something that anyone has ever seen before? I would not expect that it complies with Code. I think the top block has been filled with mortar but I don't think that the pier is filled with mortar all the way down. The piers must resist vertical load as well as lateral wind load transferred from the cottage structure above.

 

[hokie66]

Mortarless piers can work, provided that the interior is reinforced and concrete filled, so that the blocks just serve as formwork. But based on your photo, that is not what has been done here...it has just been slapped together, and I think that approach has been carried throughout. Where do you find these abominations, anyway?

 

[CELinOttawa]

That's just awful... And be careful from a business stand-point as well. The majority of times I've been stuffed for the payments have been for mobile homes and (cheap) cottages.

 

[ajk1]

I did not find this contractor. A friend asked me to look at it, after it was all built. I told him 1.5 years ago, before he built anything, that he should be sure that there was an engineer's seal on the drawings, but he said that was not necessary, that the contractor was very experienced, and that the building department had approved it! I am not sure that the building department knew he was going to raise it up in the air like that (so that he would not have to pump the septic tank).

I find it is almost impossible to tell a layman that they need a structural engineer. When it comes to structural engineering, 99% of laymen are sure that they know more than any structural engineer. After all, they have all hammered a nail into a piece of wood. Really , what more is there to know? Anyway, they can save the engineer's fee by going directly to the contractor.

 

[SkiisAndBikes]

Unfortunately, this is common cottage construction from the old days... dry stacked blocks. No engineering, often no permit and often holding on by a thread, although in many cases the thread has held for 20+ years.

There are approved, prescriptive pier details in the Canadian modular home foundation standard, if you wish to see how they layer mortarless hollow block with plywood.

What is shown in the photo is way beyond my comfort level and needs to be addressed.

 

[ajk1]

Thanks SkisAndBikes for the useful thoughts and information. I had not thought of the Canadian modular home standard. I will see if I can find that on line. If I cannot find and download it, I may have to come back to you, if that's ok.

When they built it mortar-less in the old days, did they build it as high as shown in the photo?

Does the modular home standard allow mortar-less to be built so high?

Any suggestions on how it can be made to work or how to fix it? I know that I have to add piers anyway because the wood beam between piers is over-stressed.

If say there is no tension in the piers under P/A + M/S, can they be considered ok? I have no idea yet if this will be the case...I have to to do calculations still.

 

[darthsoilsguy2]

mobile homes do this, but they use anchors and strapping to hold the structure down, and limit amount to less than shown. that photo gives me the creeps

 

[dhengr]

Ajk1:
RE: Your post of 29 Aug 14, 14:50, you said:
“That would be very expensive...have to temporarily support the cottage while pulling out the old beam. I would expose myself to liability because the contractor would sue me for not designing an economical fix that he would have to pay for. Then I would not sleep at night. If the cottage were not all built and completed, then I would agree with you. As a lawyer pointed out to me 30 years ago, when I first prepared to act as an expert witness, repair/remedial measures are not the same as new design. There is a professional and legal obligation to minimize the remedial costs, consistent of course with providing a safe design that can be shown to satisfy the intent of the Code.....”

You should walk away from this if the contractor and cabin owner on not welling to pay you for your effort and time, and if they are not willing to pay to fix their self made mess properly. The owner claimed the contractor was experienced and knew what he was doing, and the owner was advised that he should retain the services of a Structural Engineer, but didn’t think he needed one, so they made their own mess. And, you shouldn’t stick your neck out to do fix it on the cheap for either of them, that’s real liability exposure. Obviously, I don’t mean run up the bill either. But, what the lawyer should have said or meant, is it is never easier to fix a crappy job than it is to do it right in the first place. It invariably looks like a cobbled mess and is almost always more expensive than having it done right in the first place. But again, these are their blunders, not your’s, that you are trying to fix. Get you fees in advance (a retainer) and return what you don’t us to do a proper analysis, design, drawings and specs., etc., when you are done and satisfied with the results. You might also consider a memo. listing the defects, which you are aware of and can see, and general fix approaches, without details, until you are paid. This letter/memo. would go to the contractor, owner and the building officials. I agree with Hokie, and wonder how keep finding these abominations?

 

[ajk1]

Right.

 

[KootK]

This is a bit extreme but you could construct shear walls between piers? Mane even cast new concrete around them.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

 

[ajk1]

Because it is accessible only by boat, casting concrete walls is perhaps not practical. Constructing some type of shear wall, perhaps masonry, right up to the underside of the built-up beams, is worth thinking about.

Or maybe it can be a wood stud wall with sheathing each face, that can act as a shear wall. In that case, pour strip footing, then place masonry block to 6" above grade, then build stud shear wall on top of block tight up to underside of built-up beams.

 

[KootK]

Right. Maybe you can arrange things such that the new wall supports some or all of that 4-ply beam that's been giving us grief.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

 

[ajk1]

yes that is my thinking too.

 

[CANPRO]

At least you have lots of access for the repair. Maybe you could shore up 1 or 2 at a time, remove the top block and reinforce and pour with concrete/grout as had been suggested above. Whatever the fix, I think the contractor should be on the hook for at least a part of it.

As an aside...your other thread says the exterior beam is built-up 4 ply but in the picture you posted in this thread looks like it is 2 plies. Might just be my eyes playing tricks.

 

[ajk1]

How would they get the rebar into the pier if only the top block is removed? Wouldn't they have to remove most of the block?

 

[Canuck67]

To me, a reasonable approach to repairing this would be to A) provide temporary support, B) remove existing blocks (stockpile for reuse), C) Pin to rock or provide leveling footing, D) Construct new pier (16"x16") with reinforcement and grout. With this method, all existing blocks would be reused. Capacity of the piers would be greatly increased.

 

[ajk1]

Yes, that may be what will have to be done. Thanks.

 

[ajk1]

..although it is quite a load to shore for...