You are here:

Flooring and Carpeting/Basement Floor- Difficult



I am trying to finish a remodel on a home built in 1974.  (I love new construction!)

The basement floor is uneven.  I suspect there is no vapor barrier beneath the slab. The slab was stained by a cat.  Numerous attempts to clean the slab with bleach, Liquid Green, and citric acid did not cure the smell.  My best guess is the odor emanates from the cracks.  The slab has many cracks- and I've tried to correct the unevenness with self leveling compound- and I've hit the cracks with cement caulk and Red Gard.  Finally, I've covered the area with Red Gard.  The odor seems to be addressed.

I've concluded the best way to finish the floor is with carpet in most areas.  

Any specific recommendations about the type of carpet pad would be most appreciated. Best brand?  I think the pad should be breathable. The slab may get moist due to capillary action in the summer.  (Home is in Alaska- no moisture problems in the winter).  Also, I've been led to believe the best way to secure the tack strip would be with an adhesive- rather that using concrete nails.  True?  Or should metal anchors be used?

A few areas I'd like to tile- like a kitchen area where carpet is not a good option; I am considering a crack isolation membrane.  Is the best way to deal with the unevenness when applying the membrane- or when the tiles are set.  Somewhere the mortar will need to be thicker...  Better to get the floor flat with the membrane?

Also, there is a bathroom in the basement that has an ugly tile floor. (Good installation- just 1970's ugly colors)  I think the best option to cover this floor is with a carpet- so the tile will not have to be ripped up.  I think it was glued down.  Is there a carpet that works best in bathrooms?

This home has been a challenge.  Your expertise is welcome.

Thanks very much.



I will go in order as best I can. First the padding, I am going to suggest "Felt" or synthetic padding which is made of fiber instead of foam. It is used widely in commercial applications due to it's density and economic costs. Density is a key factor when heavy foot traffic is expected. But in your situation the breathability is what I am looking for. It has no plastic protective membranes and is made of fiber that will allow the transpiration of moisture somewhat better then a foam residential padding with a plastic membrane. It might not be as comfortable underfoot as you would normally encounter. This is purely a subjective attempt to alleviate some moisture issues and I am not entirely sure how well it will work or how extensive your moisture issues are.

Typically it is sold in terms such as these: Commercial Padding / Synthetic Padding / Rag Pad / 24 oz, 32 oz and 40 oz. In the old days it was in fact JUTE padding and that is expensive today due to the NATURAL source it comes from. So the carpet and pad wizards made a synthetic version. Obviously the greater the ounce rating the more expensive and thicker it will be ...usually from 1/4 " - 5/8" The 32 oz is about average at 7/16" and is very popular.
One of the many manufactures and one of the most well known....

Home Depot and Lowes may or may not have these items..and they are full retail. So if you have any carpet suppliers in your area that sells to installers and carries all the sundries, try to shop there and compare.

The Red guard may peel with capillary action in the summer or the worst season you experience.
You may want to get more aggressive and spend a tidy chunk if it does. I would go this route if you are at end of ideas.

I have used it for wood flooring moisture issues on slab. It is a great product and has the highest rating (12 lbs) of moisture stopping ability. It dries hard like a green candy apple plastic. It flows out smooth and settles evenly once you roll it. And any padding can be applied over it.

Attaching the Tack strip with adhesive is commonly done in troublesome areas or over a tile / stone floor where a nail can never go. In the early days we used Liquid Nails and today the industry has even better products sold in the typical 10/30 oz. cartridge and applied like a bead of caulk. If you can, try to get a few concrete nails (1/2") to hold into the slab. Use of a NAIL DOWN BAR is extremely handy for the little nails. Or a magnetic nail holder.

Remove the factory supplied 9/16" nails manually and replace with the 1/2" or buy the tack strip called TACKLESS with no nails at all.

Chemrex CX-948 is the go to adhesive. If you can't find that then PL400 is next in line.

Found this ...never tried it...interesting


In minor cases I will use various trowels to apply thicker amounts of mortar to make my tiles even / flat. Including back spreading the tile itself. The typical trowels 1/4 x 1/4 and a 3/8 x 1/4 and a 1/2 x 1/2. I will apply the mortar to the floor after all lay out and prep is done at the highest point reasonably possible. This means snapping chalk lines and spraying them with hair spray to keep them from disappearing. Working a 4x4 or 6x6 area I will level the tile and apply spacers and clean my edges so no remaining mortar interferes the next day. I then walk away and allow to dry over night. The section that is completed will be the height I work off and strive to achieve overall.

If you are going over a DITRA membrane snapping lines wont be of much use. So purchase some metal framing studs 2-3 bucks, 8 or 10 feet long. Use them to see the low and high spots on the floor by laying them on edge. Swing an arc and look for the voids under the edge or the rocking of the stud as it rests on a high spot. Determine how you want to fix the unevenness.

Measure and layout the tile for reasonable fills at least 2" or more. If you are a perfectionist you can have the tiles on each side of the area the same size as depicted in many HOW TO books and guides. But that is not necessary ..close is good. Once you lay the membrane you can refer to the measurements you made and lay a section of steel framing down to act as a straight edge / guide where your main line and start will be. From that point on the tile and the spacers will keep you pretty square. You can do a 3,4,5 triangulation to start with and check for square while the tile is still wet.

If things are more severe I will self level or manually trowel a floor patch to the low areas. Severe is more than 3/8"- 1/2"

Carpet in a bathroom:

I cant really say what is best or better here...I like tile / stone. I love using my knee pads and scrapers and if needed my demo hammer to remove old and install new. Over a period of 3-5-8 years any carpet in a bathroom will become soiled enough to be unsanitary...maybe sooner. Any Nylon carpet will endure longer than Polyester...but if you plan to replace often then less expensive is better.

OK That's my 2 cents...

Feel free to holler back anytime,


---------- FOLLOW-UP ----------


Again, thanks for the comprehensive response- it is much appreciated.

I note in your answer that you recommend using a metal stud straight- edge for leveling.  Its cheap, and effective.  I assume you are using lasers for some of this type of work.  If so, do you have a brand preference?

Also, have you heard of or used a padding called- "Stainmaster, Carpet Cushion, with odor control".  They claim this is an open cell, breathable pad.  It would also seem appropriate for basements.  You are correct- the big box stores, Lowes, Home Depot do not have expertise with these sorts of breathable pads.  Even some of the local carpet/flooring stores are lacking a bit with regard to breathable pads.

I think I will go with the DITRA membrane.  I've had good luck with DITRA over wood floor- tile applications.  I'll set the DITRA as perfectly level as possible- then try your approach by setting a section of tiles as a reference point to work from.  That is solid advice.



MP ,

Funny you should ask about lasers. Yes I took a plunge and studied them for a week , suddenly Home Depot was cutting the price on the model I wanted and I bought it for 3 bills. The laser will allow me to line out Mall hallways walls ...ceilings and perpendicular lines to boot all at the same time whilst playing my favorite Zepplin OK it doesn't play music , but it looks like it might fly away. Very similar to this...

So yes any laser that shoots 2 lines NS / EW at the same time is a good tool
I shop at the Home Depot because I have a charge card there and they beat the blue box by 10% everyday all day.

Padding ...the odor control thing is a mystery to me. I think it is a superficial bell and whistle. I am never around long enough to see a difference.

Thanks for asking


Flooring and Carpeting

All Answers

Answers by Expert:

Ask Experts




20+ years flooring installation ...carpet,wood,tile and vinyl. Residential and commercial. I do not sell the products , just install what ever the shop / customer has purchased. I actually love seeing the finished project completed and it gives me great satisfaction to help others acheive that goal. If I don't know the answer I will say so, and then I will recommend another expert for you. I may even research the subject and answer to the best of my ability ...including links to my sources. I wish you all success Chris


20 years as an independant contractor

H.S. diploma A.S. agriculture Mt San Antonio JR. College

Past/Present Clients
Gene Bonas and Kevin Churnock Inc. Sheward&Son&Sons Century 21 Forte Const. Famous Footwear BOSE Corporation Homebodies General Contractor Perry Floors, Tri Cord Flooring T.J.'S Supplies

©2016 All rights reserved.