Hey guys,
Heres the deal. 1880's colonial, balloon frame construction. Fieldstone foundation with brickontop to sill plate. about 6 ft of fieldstone and 16" of brick dependingon the spot.

The house is 33ft long on the back side. Situated like this. 23 ft fieldstone and brick from left to right, then a concrete block bulkhead, then another 5ft of fieldstone and brick.


Back side of the house sill plate rotted due to water damage. Bricks mortar had turned to powder or much depending where the water was. The bricks were heaved in, in several spots in the 23 ft section.

We jacked the house up to level it out, then removed the brick down to the fieldstone in the 23 ft section.

We brought in a mason who suggested pouring a concrete footing on top of the wall to level out the irregularities in the height of the rubble foundation. From there he would lay a course of block. He sent some guys over who apparently never built anything load bearing. Apparently they threw left over bricks in the form and covered over them with portland.. no rebar or webbing. I found out afterward.. I removed the forms and to my horror were massive gaps in the footing and bricks sticking out every which way. heh. No money lost though.

So now I have to remove that slab... Shouldn't be too hard since it was poured pretty worthlessly anyway.

So after that I talked with some folks. One of whome suggested that I should NOT use a cement footing and block because fieldstone will move and crack the foundation.

I was thinking this could be remedied by pouring the concrete in slab sections (with rebar and such) over the large rocks and separating each section or slab with sill-seal or a sand mortar joint. Essentially make a form for each section and on the ends (inside the form) use a strip of sill-seal to create a small gap and gasket between each slap to allow it to move with the fieldstone and reduce the likely hood of cracking.

Then after that has settled lay the single layer of block needed on each slab in the same separation format using sand mortar between the vertical joints (only, regular mortar mix everywhere else) at the end of each slab section.

Or do you think I should just pour the full slab and build the block.

Other questions, should the block be filled with portland as well since I will be laying a sill ontop of this? Could i use type s mortar mix for this as well?

Your suggestions would be great!

Thanks!
Joe

 

[many expletives deleted].

wow.

first question: where are you? please tell me you're not in earthquake country.

you might want to consult an engineer.

load-bearing block walls should be filled with continuous medium-to-high PSI concrete, have a rebar schedule within them, and tied to the wood structure with bolts. all bets are off when you're talking about laying those walls on top of a stone foundation, however. for example, how will the block wall be integrally tied to the stone "foundation?"

 

Im in Massachusetts. No earthquake issues here.

As for the house being tied in to the foundation. the sillplate does not appear to be tied to the foundation except by gravity. Its a two story colonial. The only thing that ties the brick to the foundation was sand mortar and gravity. Rebar probably wont be needed inside of the block as it will only be one block high, and lateral shear force wont really be an issue.

 

from your o.p., i got the impression that the block/brick combination was higher than 8". after a re-read, i see what you're saying, but i have a couple of questions.

why would your stone foundation move? it's been there for 130+ years, right? has it sunk? i read that the top isn't level. was it level at one time? how far out of level is it? have you put a transit in the crawl space to get an idea of how level the entire foundation is?

if it was mine - even in the northeast - i'd put short rebar dowels in the top of the stone every 4' or so, lay 12" (12D x 8H x 16L) block over them, fill it with concrete, set j-bolts in the concrete at around the same interval as the dowels, and bolt the house to it. i would eliminate the footing-on-the-foundation idea.

at the very least, you should fill the blocks with concrete, not mortar.

 

Its 16" from the top of the fieldstone to the where the sill plate will be. The top of the fieldstone is not level originally when it was layed nearly 130 years ago. It has different sized rocks so they do not all end at the same height. They used brick/mortar to level it out. The fieldstone wall is about 5 ft, and its a full basement, no crawlspace. maybe I will get some pics.

 

What kind of masons are in Massachusetts?

Many of the homes in my area are 1800s and 1700s a couple of 1600s

Hears how we do it. A rough form to pour 8" on Crete with 1/2 bar in it. As the concrete is wet we set long 1/2 anchor bolts up through the new plate hole and in the fresh Crete.

After that we either lay double brick wall and Flemish bond it ( The historical way) and once all is set up tighten anchor bolts. Other times we use 4"x10x16" solid blocks and parge them.

All this talk about rebar into rocks and segmented slab/mini caseins/ expansion etc. Is a waste here. My reasons.

The house is basically a dry laid stone wall that more then likely had Lime mortar in between the stones. Age removed that. Ergo house leaned/sank. The new Crete cracking if more movement showed up is no different then segmented expansion pours. It us humans that want to see a pretty straight line for a crack. In this case its not a walk/patio. Think of the 100s of "cracks" in the stone wall now...

As mentioned this isn't a shear situation. Its also balloon framing that handles movement well. If it wants so sink it will. Drilling into the loose rock will actually hold the rock to the footer not the 10times stronger footer to the rock. The new footer is a "band" footer for the houses footprint / presto the boots.

 

21boat,
Thanks so much for your reply. Thats some good info. I guess I was thinking that if it was not segmented, the concrete could crack in several spots close to each other and cause it to lose its holding properties. The 1/2 rebar should do its job here?

The other problem I have is that there is no sill plate and I will have to slide the new on in under the joist ends, so I can not bolt it to the footing in the manner you described.

I guess I could use some of those long nuts ( i forgot the name for them!! ) that you use to tighten threaded rod together and have it meet the top flush. and bolt down into that from the top of the sill plate. How often would you place one of these tie ins?

Also what type of mortar do you use on the 4x12x16 blocks?

And could you explain parsing?

Im really happy to hear from someone whos done this before.

 

The code here for 1/2" anchor bolts are every 6' and no less then 1' off the corners. I went to look up the "keystone mortar" we use and up pops pictures of two old buildings in my city. My city/county is used for a Bench mark on old masonry buildings Restoration in the U.S.. Alot of the buildings here are in the 'National registry" "Black Horse Inn" American Tobacco Co."

Keystone Preservation Group

You can use Portland cement to lay the block or Mortar. The diff is one has lime already in it and one does not. For instance a 92 lb bag of Portland Cement requires a half bad (52lb) masonry lime to 32 shovels of sand or ( 400 lbs ) of sand to a bag of Portland. The 72lb of Keystone Mortar takes 16 shovels of sand to bag of mortar ( the lime is already in the Mortar Mix)

Parging is the old way of saying Stucco. To parge the block lightly wet the block. Apply a scratch coat of mortar. Use nails sticking out of a board after it sets up fairly well to scratch. Then apply another coat to finish it. For looks you can use a wet horse hair brush and swirl a texture into the almost set up finish coat. The best for a real smooth coat is an old foam mattress sponge. Wet it and smooth down the finish coat.

You won't need a 12' wide solid cement block for the plate. Are you planning to use a 2x12 treated house plate under there? 4 high 10 wide and 16 long solid is more than enough for a sill plate to sit on. If fact on framed houses its only a 2x6 plate even for two stories. A 6" solid is fine here or 8' if that whats your new wood plate will be.

This is the anchor bolts that are used here. They come in short or very long lengths at the masonry supply house.
50 Pack, 1/2 x 10", Steel, Anchor Bolt, With Washer & Nut, Coarse Thre

4" solids like to get ahead of 16" bond so be aware of that when you lay them. lay out the anchor bolts and set them when you pour the Crete. Predrill the plate since its up in the air. If you try to set anchor bolts the other way you will start swearing.

 

Good info,
But there is no plate on the house yet. The old one is gone. It was 4x6, I am replacing it with PT 4x6 which measures 3 5/8 x 5 5/8 or so. all the stud/joist ends had rotted as well. I am sistering every stud from the center beam to where the sill plate will be going.

The only way we can do all of the repair work properly is to install the sill plate last after everything is in place. Or else nothing will go in place because the studs have dropped independently of the joists and need to be jacked up as we put the sill plate in. So I cant have bolts sticking up out of the block.

Speaking of block, is there any reason you would recommend I not use concrete 4x8x16 hollow block filled with concrete for this job?

Also whats the reasoning for using a Portland/Lime combination rather than just the quickrete Type S bagged mortar mix?

thank you!

 

A 4" hollow block is not to be laid sideways. Its to be laid up right which its only 4" wide. Thats the whole reason the make solids to take the compression. Filling a block seems redundant. It would need filled and packed to get any strength.

Can you explain why you want to fill a 4" block?

Its junk to work with.

What the public doesn't know that Those ( crets ) is terrible to lay anything. Walked off of a job because of it. Also the best bang for the buck in cost and quantity is making real Mortar as I posted

 

I meant 8x8x16 blocks.

Can I use just any old lime I buy at the hardware store?

 

[QUOTE=JoeMoe;1567606]I meant 8x8x16 blocks. Can I use just any old lime I buy at the hardware store?/QUOTE]

Its a little different. Go to a masonry supply house and get the supplies there and all will be matched plus they can answer any last minute questions.