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Patio slab, mudjack or tear apart?

Posted by dinosaur1 5 (My Page) on
Wed, Dec 14, 11 at 18:40

I've determined my patio poured slab slants towards my house at the North East corner.

Typically during windy rain storms a small trickle of water appears along my poured concrete wall (4in long by 2 in wide) at the same spot. I have a rec room downstairs.

We had a forecast for rain with wind today so I covered my entire patio which is 12 x 12 with a plastic tarp, taped it and pitched it away. I added a extra piece of tarp on the North East corner of the patio.

There was NO WATER trickling in my basement today at or near the problem area.

My dilema:

1) Should I mudjack the patio slab? Eventually the patio will start to sink & pitch towards my house after 3-5 years because of the frozen midwest ground.

2) Pull the slab out, grade the former slab area with brown landscape dirt, add fine street gravel, then pavers of my choice?

Will pulling the slab out cause a bigger problem with a basement leak? Reason being the former slab area is now exposed, but graded + pitched with dirt/gravel away from my house?


Follow-Up Postings:

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RE: Patio slab, mudjack or tear apart?

I can only answer part of your questions as no direct experience with mudjacking here. (But I hear it works.)

As long as you end up with a patio surface that slopes in the correct direction, you're good. Tearing out and fixing grade will not increase water infiltration. (With known water issue you might increase toward maximum allowable pitch.) Make sure to properly compact subgrade (with a machine) before rebuilding. (And don't use a more porous substrate to build up grade at the house.)

If you know that mudjacking is a viable solution, then determining factors seem to be primarily cost and finished aesthetics (and any incidentals that might affect the job finish and flow.) Weigh all of that to figure out what works best for you.

Settling has more to do with inadequate backfill and compaction than freezing. All parts of the patio freeze and relatively uniformly at that.

General Notice to forum readers: I have changed my name to Yardvaark. It was formerly Yardviser. I did this to have a less egomaniacal sounding name. Hope it's not too much trouble to get used to.


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RE: Patio slab, mudjack or tear apart?

After a rainstorm there is a puddle of water that forms around our patio step closest to our home. In your opinion should I mudjack the patio (knowing that it will settle back down after a few years) as well as pitch some brown topsoil away from the wall 1' per foot?


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RE: Patio slab, mudjack or tear apart?

The patio will only settle in the future if there is further decomposition of the soil (or things in the soil) below it or there is undermining by water. You should add soil near the house in order to create positive drainage away from the house if you don't already have such a condition.


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RE: Patio slab, mudjack or tear apart?

So if I add the brown topsoil next to the foundation...
Is mudjacking still needed at that point?


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RE: Patio slab, mudjack or tear apart?

OK, I don't understand your questions about the topsoil - where it is, what you want to do with it. But ignoring that, it seems to me you are looking at the area next to the house as the source of your problem. I think you need to step back and take a larger view of your patio.

First, how is the height relative to the stairs, and house? Is it low, correct, or high? And second, what is the level and condition of the patio overall? And finally, is this the patio you want where you want, or should you think about this situation as an opportunity for replacement?

If the patio is one slab, and it slopes toward the house but is at the correct level when it gets there, your problem is not that the patio is too low near the house, but rather than the patio is too high on the outside edge.

If the patio is low by the stairs, then mudjacking should level it to its correct level. If, however, that will crank the patio up too high at the steps, then you are maybe better off looking at making a new patio (if there is no way to drop the level of a slab, which I don't recall ever hearing about). If I remember this one from your previous threads, it's not design magic :-) and you might be able to do something nicer or better placed not to mention that the back of your house is next to a busy street, yes? Have you got room for a side patio?

Finally, on a smaller scale, you could maybe solve your problem with a tiny adaptation that is very easy to do. What you need to do is redirect the water that is flowing across the patio to this low spot. Experiment with a long 2x2 or similar lumber to figure out where the water should go instead. You get a bit of cement or mortar, and make a little ridge along the 2x2; a tiny concrete berm or wall, an inch high or so (then remove the wood). The water will follow your little diverter.

I made a little diverter like that about a foot long with about 25 cents (Canadian!) worth of cement, and solved a water-in-the-basement problem that had plagued us for ten years.

Karin L


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RE: Patio slab, mudjack or tear apart?

I was told to add more brown topsoil because what I have is a pitch towards the house. After adding the topsoil it needs to be compacted. After adding a plastic sheet on my patio slab and pitching it away from the house I now have no water in my basement. I have 2 problems : a patio slab that is pitched towards the house and then the grading along the foundation of y home is not graded good enough which is where the brown topsoil comes in.


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RE: Patio slab, mudjack or tear apart?

dinosaur1,

I think you are looking at the situation in a way likely to lead you to the wrong action. The patio is not your problem. It may be a major cause of the problems, but it is not in itself the problem. First you need to clearly define all your objectives, such as stopping water from entering your basement and preventing a puddle from lingering on the patio.

You may have other solutions that don't require the removal or mud jacking of the patio.

As for mud jacking, it is important to assess if it will provide a permanent or temporary fix. Things to consider are the age of the house and patio. Were they built at the same time? What is the underlying soil strata. Was the patio grade poured wrong initially or has it sunk? By how much? Has the sinking stopped at this point or is it continuing? Why? Is there a subsurface drainage near the basement footing? Can the drain be eroding soil from under the patio, leading to the sinking?

What is the general soil grade from the house to well beyond the patio in all directions? What is the climate you have, yearly rainfall, and magnitude of larger rain events? Where does excess rainwater flow and how does it exit your property? How permeable is your soil?

These are some of the questions that need answers before you choose a course of action. As karinl said, step back and see the bigger picture.


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RE: Patio slab, mudjack or tear apart?

to answer your last question, if patio pitched to drain toward house, you need mudjacking or to correctly replace the patio. I presume your talk of "adding brown topsoil" is about areas adjacent to the house that are NOT underneath the patio. You surely will NOT compact areas such as that. Those are for planting.

If you replace the patio you will build up the grade below it to the proper height with subsoil or if it's not very much grade change, crusher run (driveway gravel). In most cases one would use whatever occurs naturally below their topsoil. This is a detail that varies a lot depending on your area. You just don't want to use topsoil which will decompose further....i.e., you don't want something that has organic matter in it. You want something that is made originaly of rock and will not further decompose (which will cause settling.)

You could get better answers from forum if you post a picture(s) that clearly illustrates the problems you are talking about.


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RE: Patio slab, mudjack or tear apart?

Ok I can post some pics later tonight.
Can someone answer me this?
If the patio isn't the issue......then why is there no water in my basement after placing a plastic sheet over my patio which was pitched away from the foundation after a 1' rainstorm? I did this as a test.


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RE: Patio slab, mudjack or tear apart?

One problem is that you are getting water in your basement. If it weren't, would you be considering doing anything about the patio? If you mud jack the patio and water still gets in the basement, you fixed the patio but did you fix the problem? The result you want is a dry basement. Anything that achieves that is a fix, and a permanent fix is better than a temporary one.


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Pics

More pics

Here is a link that might be useful: Patio pics


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RE: Patio slab, mudjack or tear apart?

[Off topic: Hmmmmm...I don't recall if I mentioned in this thread changing my member name, so as a disclaimer I'll mention it here. I am leaving Yardviser behind and shall henceforth be known as Yardvaark. Ink called me Yardie once which I liked and tried for, but it was not available. :( ]

Thanks for posting pics; they help to understand relationships. The pics don't show an obvious slope, but based on your comment about water puddling by the step after a rain indicates patio slopes toward house...or at least does not have sufficient pitch away from house to drain properly. I think your experiment with the plastic sheet was a pretty good one and it's a likely bet that you've identified a source of water entering the basement. Your proposals of mudjacking or rebuilding the patio from scratch are viable. As I said before, without direct experience with mudjacking, I don't know how much finesse they can put into the operation and have the end result be what is envisioned in terms of exact finished elevations. Someone else may want to chime in on that. If rebuilding from scratch, there'd be no question that you could take care of properly compacting the base and achieving desired elevations.

I'll throw in one more possibility. You could add another surface layer of mortared thin-set paving brick over the entire patio surface and achieve the corrected grade with it. (And have a nice brick patio to look at.) In doing this, you would make positive drainage with the new surface (just like you would do if building a new patio) and the differential in slope would be created by the unseen mortar layer underneath the brick. It would vary in thickness, being thickest at the house and thinnest at the side of patio nearest the trees. Hypothetically, let's say that the patio right now is 1/2" lower at the house than it is at the outside edge. If you raised its surface 3" at the house and only 1 1/2" (which is probably about the minimum possible with this material) at the outside edge, you'd end up with a 1" pitch differential (measured from level) across the entire patio surface.

As I see it, the problem you MIGHT run into with mudjacking or adding a layer of thin paver bricks is that you'd be raising the patio level at the house and must examine if that creates a situation where water will eventually cause wood next to the patio to rot if it infiltrates the crack between the house and patio. After examining this issue there may be various architectural solutions at your disposal. (Even an awning might be useful.) I'm not saying that it will be a problem...only might be and needs examination.

As pointed out by karin earlier, if the grade at the house can't or shouldn't (because it's already at the desired elevation) be raised, then the problem is that the patio's outside edge is too high and needs to be lowered. Doing this also depends on what's beyond and I see you have a row of trees that probably wouldn't like this. For sure, fixing it, at least, means a patio tear out and rebuild.

This isn't part of your question, but I notice that there are what I think are Spruce trees. They are going to grow huge and eat up your patio space. As they eat the space you'll be faced with the dilemma of limbing them up or shearing them back. If you're going to shear back, you'd better start doing it very soon. Shearing will not work if you allow them to grow too much and cut into the "dead zone" (beyond the foliage) when you trim. As then, they will not regrow new foliage and you'll have no choice but to limb them up. And you should shear not allowing any upper branches to overhang and shade lower branches as that will cause them to peter out and die off.


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RE: Patio slab, mudjack or tear apart?

Hi, I just joined to add my two cents to the response. After looking at your pictures, I believe you have cavities under your slab which allow water to accumulate and since it's below grade, the only place for it to go is through your drain tile or basement. The patio slab should slope away from the house at 1/4" per foot to provide drainage. Failing that it, it can be left as is if all voids underneath are full. Sandjacking can accomplish that if it's available in your area. Mudjacking would still leave voids, because it can't fill absolutely with a viscous material, (which is why it eventually resettles, by the way). Good luck.


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RE: Patio slab, mudjack or tear apart?

One should consider whether the patio has stabilized. If it is continuing to sink on the house side, the mudjacking or an overlay will only be a temporary fix. Additionally, if the new patio grade is above the foundation elevation, it will probably lead to a rotted sill plate and an expensive repair.

There are any number of possible fixes for the basement water problem. On the limited information given, only one stands out as a permanent fix. If the sole cause of the wet basement is the patio water and if the only water on the patio is the rainfall directly on it, the answer is a roof. No water on the patio means no water in the basement. With a roof it doesn't mater what the pitch is or whether the patio is stable.


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RE: Patio slab, mudjack or tear apart?

As has been said on this forum before: attempting to solve a drainage problem from a distance is fraught with danger. At best we can ask questions so that you go looking for the solution yourself. pls8xx is on the same wave length and the questions contained in that last paragraph are simple and cut to the chase. Where does the water come from and how does it get to its destination? Is this patio fairly new, what was there before, did that leak into the basement, was the house damaged in any way during the construction, does the water go under the patio at any point?


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RE: Patio slab, mudjack or tear apart?

These are the relevant previous threads I was able to locate with Google's Advanced Search. The picture links on those old threads don't work for me.
"Mudjacking Patio" thread
"Patio Slab Question" thread
"How To Make Pitch Away From House" thread

IIRC, a photo on one of the old threads showed that a sump pump discharges between the patio and the corner of the house on the side with only one window. I don't know if that's the side of the patio where the basement leak is located.

Where does the water from the sump pump go? From the new photo, it looks like it might not be able to drain out of the area between the house, the patio, and the spruces.


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RE: Patio slab, mudjack or tear apart?

here are some more pics....

Here is a link that might be useful: More patio-house pics


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RE: Patio slab, mudjack or tear apart?

Looks like new pics show that once you get drainage going to far side of patio, you'll have no trouble getting rid of water as there's plenty of slope beyond the trees.


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RE: Patio slab, mudjack or tear apart?

Missingtheobvious

I have a 15ft hose that goes to a ditch 15ft away from the house


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Drainage

Yardvaark
what would be my next step at this point to get that done correctly?


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RE: Patio slab, mudjack or tear apart?

I have a 15ft hose that goes to a ditch 15ft away from the house

I'm glad to hear that.


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RE: Patio slab, mudjack or tear apart?

It's fairly likely your patio slab is 4" thick. Scratch back the landscaping material where the patio meets the vertical foundation wall, on either side. If need be, take a hand trowel and excavate until you reach the bottom of the slab and a little below. You will be able to see if there is a void under your concrete and you can probably insert a flexible pipe/handle/garden hose into the void and push it until you hit something. My experience has been, there are voids under every flat slab that meets a vertical wall. Normally 4-6" where the excavation for the basement occurred. It tapers out to about 4-5' from the wall where the slab will meet the ground again. If the void is 4" deep by 2' wide by 12' long you will store 80 gals of water from every rain event. Most of that will soak into the soil but once saturated, it can only dissipate through you basement or drian tile.


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RE: Patio slab, mudjack or tear apart?

Thanks for the heads up MTO I had no idea youse had been down this way before but the old threads suggest that dinosaur is looking for a particular answer that he hasn't found yet rather than doing the necessary research to uncover the problem that will lead to the solution.


Anecdote alert!: I had several telephone 'conversations' with a guy who didn't want to pay me to come and have look at a way to disperse the standing water in his small back yard. He pressed and pressed so in an attempt to get rid of him, to my professional shame I advised him to pin point the lowest point in his yard and dig a soak away there. As it turned out, this new development was built on the site of an old brickyard (tell me what bricks are made from)and the lowest point in his back yard was at the back door.


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RE: Patio slab, mudjack or tear apart?

the other idea that I had is to rip out the patio slab, grade it properly and make a deck with footings over it. Suggestions?


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RE: Patio slab, mudjack or tear apart?

If when once fixed the patio tilted so that it pitched to the outside edge, but water collected there because the adjacent soil was too high, you would have to lower by removing some of that soil (or stones or whatever) so the water could get out. Don't create a dam that creates a puddle. If you had to channel that water on through the tree area that would be ok. You'd only have to have the channel deep enough to allow water to escape and no deeper. So we're talking something very minimal. Blend it into the surrounding grade so that it's not noticeable. I'm not talking about putting water in a pipe or anything like that.

Dino, The deck, as you proposed as an alternative, is also a good solution. It'd be more enjoyable than the patio because of being level with the house floor. But if you did it, you'd want to make it a little larger than the patio is now.

Sandchuck, I don't know where you are, but I've been in several areas and my experience does not jive with yours as far as "...there are voids under every flat slab that meets a vertical wall." I've seen a few, but it's always been a case of undermining by wild running water that is usually obvious from the slab edge. An even easier way to tell if there a meaningful void below a slab is to tap on the slab with a weighty pole. You can hear the difference of the tap sound if there's a void.


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RE: Patio slab, mudjack or tear apart?

Yardvaark, I live in North Dakota, so frost enters the picture here. Water accelerates the normal settling around foundations which causes the voids I speak of. Still even with normal weathering, voids will develop and hollows exist at a greater frequency than common knowledge would allow for. Add a down spout without an extension and you'll see the void sooner, rather than later. Different soil types also contribute at different rates. But, for the example given by dinosaur, I feel confident my prediction will ring true. Tapping on the surface is also a good signal.
All of this being said, the solution to the problem can be as simple as fill the void. Even if the surface of the patio slopes the wrong way or is level, the relative volume of water after filling the hole will be much less. If you fill the void with sand, the sand holds the water in suspension, the excess runs away, and the leak stops. That's what I've experienced. I liked your advice to establish surface drainage. Many people overlook that simple, yet effective method also.


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RE: Patio slab, mudjack or tear apart?

Sandchuk, it's my rule of thumb about drainage: always keep runoff water on the surface and avoid putting it in pipe if at all possible. Pipes and their appurtenances are prone to way more trouble than swales and the like. And surface drainage is so easy to inspect!


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RE: Patio slab, mudjack or tear apart?

Dinosaur, in looking at your photos again, I am not sure you've done enough diagnosis.

Have you had the level out there so you know whether it is the whole patio pitching toward the house, or just near/under the stoop?

Is that water in the basement right under the stoop?

I notice that the stoop is elevated, and you can't get at the part of the patio right under it. Yet I'm thinking that might be where your problem is. Seems to me you have nothing to lose by trying a small fix first - costs only a few dollars and a small amount of time, and one rainstorm.

Using a small amount of mortar, or something temporary if you prefer (wax? plasticine? silicone or latex sealer?), build a little dam, only an inch high or so, that surrounds the stoop, even sealing against the house. Or put your plastic only over the stoop and seal around the edge with super-duct tape or silicone/latex sealer. Wait a rainstorm, or run the hose on the patio, and see what happens in the basement.

That will tell you if a big fix is really needed.

Karin L


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RE: Patio slab, mudjack or tear apart?

Karinl
Can you save the picture you're talking about and circle the area that you want me to test. I'm not following


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RE: Patio slab, mudjack or tear apart?

Karinl
Are you looking at the pie with the white step. That's an old pic and that step is gone. See my newer pic with the new
step.


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RE: Patio slab, mudjack or tear apart?

It doesn't matter what stoop you have. And I have no idea where to draw a line, if I were inclined to do so, because you haven't answered my questions nor given enough information about exactly what the slope of the patio is where, or where it changes; whether the whole thing is flat but tilted, or whether the surface is mostly flat and just starts to slope at some point. I can't get out there with a level for you, and that is what you need to do to implement my little method. Your plastic sheet test determined that your problem is somewhere on your patio, but you haven't even answered where the water is in the basement relative to the patio.

The idea is simply that you determine where the slope problem is on your patio. In your OP you said you determined it was the northeast corner, but you have not told us how you determined that.

It might not really matter; even if the patio is flat but pitched on an angle, a concrete dam across it will divert the water from the basement entry point, just like one of those rain diverters that sometimes run across steep driveways. But if you know what the pitch is where, then you can more carefully place your diverter so it is minimally in the way.

A little concrete dam isn't ideal on a patio, but perhaps you can live with it for a summer or two while you figure out what to do with the patio overall. But besides that, sometimes guys prefer solutions that involve big noisy machines and lots of mud :-)

Actually, for the mudjacking option, it is probably all the more important to know exactly what the slope issue is all about. Like I asked a while back, have you been out there with a level?

Karin L


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RE: Patio slab, mudjack or tear apart?

will have to take a level and record the cement elevations and dips. A dip in the cement is visible 1 ft in front of my steps and toward the north east corner of the slab.�

I determined the north east corner of the slab is the culprit because my small leak in my finished basement is right where the north east slab meets the house. I have poured basement walls and the small leak is located at the foot of the floor where wall meets floor.


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RE: Patio slab, mudjack or tear apart?

I thought I would take a moment to tell you a story of a water problem my parents had recently.

In spring of 2011 my mother noticed water dripping from the light fixture in her kitchen. This fixture is just inside an outside wall that has an external vent in it (venting the floorspace), and above this light fixture is a flat roof deck that is surrounded by walls and drains out a scupper through the wall and then down a pipe that passes the aforementioned vent. Sorry if that sounds complicated - maybe just take away the message that the construction of the house is unconventional and the problem could have been coming from any number of sources.

So my parents engaged an engineering consultant to evaluate the problem. For $500, he told them the problem could be coming from any number of sources and recommended a contractor who could address them. The contractor came and looked, and said that the problem could be coming from any number of sources and that once he opened the wall to start looking at them he was going to have to open the whole wall and rebuild it to meet current building codes. All this was to cost $20,000.

It was summer when the contractor came, and he couldn't start work for two weeks, and then he came again but couldn't start work for another two weeks, and then he had to zip over to Europe to see his mom before he could get going, and in the meantime, rains were forecast as we got into mid September.

Finally my mom went and bought a can of roof goop and asked my husband if he could at least seal the scupper before it rained, since he's still a little more mobile than she is, and she thought maybe the scupper was what was leaking. One thing led to another as he examined the situation, and finally my husband ended up putting a ladder up from the outside and having a closer look at the vent. It should be noted that neither the consultant nor the contractor had gone up a ladder before pronouncing their opinions. It did require a 24' extension ladder fully extended (we tie two together for stability) and a safety harness, mind you, but nothing you wouldn't do for $20,000.

Upon close inspection it seemed that the flashing above the vent was bent out of shape behind the down pipe. And indeed, evidence of a leak did date back about five years to when the gutters had been replaced and a new, larger, down pipe installed (yes, it was leaf guard). So my husband focussed his efforts on this area of the flashing. Removing the piece of down pipe, he straightened the flashing and extended it a little by screwing on a new piece of flashing. He then used a couple of washers to space out the down pipe so it would not squash the flashing again.

Then we awaited the rains. So far this fall it has poured and the winds have blown, but nary a sign of moisture has there been in my mother's kitchen. A moisture meter confirms that there is no water in them thar walls.

The fix cost a total of under $50 (and was this high only because I had to buy a whole roll of flashing) and took my husband a total of two evenings up the ladder with me on crew, doing the shopping and handing tools and washers etc to him through the window.

That is why, although people on the internet can tell you many things, how to fix a water problem is likely not one of them! Your problem may be as small as one bead of water rolling the wrong way somewhere, so you could throw $20,000 at it, with mudjacking and replacing, and still not resolve it. That is how carefully you have to look at the problem. Fifty cents worth of mortar, or sealant, may be all you need to fix it. The $20,000 is saved by taking the time to figure out where to put it. And no one from a distance can do that for you.

Karin L


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