Replacing residential expansion joint?
Question:I have the black, soft, fibrous expansion joints around 2 edges of my living room floor (we ripped up the carpet to stain the concrete underneath). I'd like to replace it with something I can stain to match. I found a little bit of info about using backer rod and caulk, but it all looks very commercial - no instructions about how to do it yourself. I had a great answer to use mortar mix to fill in gaps, but I actually want to know how to remove the existing expansion joint or remove enough of it so that it is below the level of the concrete. Then do I fill in with mortar mix? Is mortar mix different than quickcrete?
Answers:
timmyjane3 is right a patch will look like a patch the color, mix, and texture are all unique to age and the person who layed the slab.
i would not suggest any masonry work under 1/2" it wont set right. so unless the expansion joints are atleast 1/2" wide and deep i wouldnt do it at all.
the existing joint/gap i would clean out with an angle grinder and blade for the materia the joint is made outta (wear saftey glasses ya might catch a couple of pieces of blade/cement/joint) and watch ya fingers
mortar mix or any other sanded concreete that can be dyed/ painted to match that dosnt contain large gravel / rocks that wont fit in the gap
quickcrete is diffrent then mortarmix
if ya fill it in i would deffinatly baseboard and then put a 1/2" quarter round trim infront of at the bottom of the base board ya know try and cover it too like the above states too
you will never be able to remove it and fill in the hole well enough to match the existing concrete. it will always look like a patch. your best bet would be to cover it with some wide base molding and quarter round.
You can dig out the expansion material usually with a hammer and a wood chisel which will be junk when you are finished. Unfortunately it will be a long process. A sand based concrete would be best but as stated above it will be noticeable. Just remember that this will be an outgoing repair because the concrete will expand and contract thus causing anything you fill the gap with to constantly crack requiring maintenance. If the expansion material is close enough to the baseboard why not paint it the same color as the base. This will make it less noticeable and easier to maintain.
If your going to remove the expansion joint I would recomend using one of the best thinset mortars for tile.They have acrylic additives and other additives for flexural strength I would think that it would be less prone to cracking than just a regular mortar.If you use the grey it might be slightly darker than your original concrete.Removing the expansion joint material maybe time consuming and difficult.I would try a grinder with a diamond wheel and go easy so you don't come out of the joint or a hammer and screw driver.I would remove as much as possible try to get atleast an inch deep if you can.Hope this helps.For the thinset you might want to see if there is a color additive you can use to lighten it and experiment a little you could also add a little white thinset to help it match.Also try experimenting with the mortar to see if you can match the concrete texture a wet sponge might be a help also wet your trowel.
Master Joint Smith has a good idea, if you do this make sure you specify non-shrink mix.
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