Can I use plastic under a concrete slab?
The fibers peel up when you trowel it, and it leaves a crappy finish. Use a good grade of stone as a base, tamp it real good, and use a good mix of concrete with some wire mesh. Ive never used plastic of any kind under any concrete Ive ever done.
Should you put plastic under concrete to prevent moisture?
One contractor says to put plastic under the concrete, it prevents moisture from coming up into the concrete. The other contractor says NO Way, No plastic, holds the water in the concrete during the drying process and can leave webbing like visual affect in finish of concrete. What is correct?
What is the best type of polyethylene for under concrete?
The American Concrete Institute considers 10-mil polyethylene with a 0.03 Perms IMP rating as the minimum barrier for under residential concrete surfaces. Thicker poly barriers such as 15-mil and 20-mil often have lower permeance values, and are more durable options.
Can water get through 6 mil concrete?
Although it may seem water-tight, this grade of material allows a lot of water vapor to pass through. 6-mil plastic often gets damaged during placement of reinforcement and concrete, creating holes that can let a considerable amount of water vapor into the slab.
Is 6 mil enough for vapor barrier?
Vapor barriers should be at least 6 mil in thickness to effectively cover the area and create a moisture barrier. Triangle Crawl Space Solutions uses both a 6 mil material for simple vapor barrier installation and a thicker more durable 12 mil vapor barrier material depending on the budget and needs of the home.
How thick should plastic vapor barrier be concrete?
The American Concrete Institute (ACI) recommends a minimum of 10-mil polyethylene or thicker for vapor retarders under concrete.
Should you put plastic under concrete?
0:101:02Why a Plastic Vapor Barrier Under Concrete Slab - Mondays with MikeYouTubeStart of suggested clipEnd of suggested clipProducts really on the ground whether it be tile wood vinyl all those things are going to have aMoreProducts really on the ground whether it be tile wood vinyl all those things are going to have a problem if you don't put down a plastic vapor barrier. That's what this is.
How thick should a vapor barrier be under a slab?
The American Concrete Institute's Guide for Concrete Floor and Slab Construction recommends that the thickness of the vapor retarder be at least 10 mils.
Should you put a vapor barrier under a concrete slab?
So yes, a vapour barrier is required under a concrete slab for a Class 1 building (a dwelling) and for Class 10 (eg a garage) where the slab is continuous with the dwelling.
Should I put a vapor barrier under concrete?
If you have a concrete floor that's in continuous contact with a source of moisture, you're going to have problems. This is why a vapor barrier under concrete is essential. Vapor barriers are a way to keep moisture from getting into the concrete.
Is plastic required under concrete driveway?
Plastic is a moisture barrier generally to stop ingress from beneath the slab. If this is outdoor in an exposed area it probably doesn't matter. I'd probably use plastic if the area is moist with little sun, just to alleviate any algae growth. It's outdoors, north facing, lots of sun.
Can I use any plastic for vapor barrier?
Plastic, specifically 6-mil polyethylene plastic, is the most commonly used vapor barrier. Plastic has a very low permeability rating, which means water, in its gaseous or liquid state, does not travel through it.
What do you put under a concrete slab?
Because concrete is a very porous material, it will absorb any moisture that it contacts. This can cause pooling. Without crushed stone, pooling water will settle under it and erode your slab. Adding a layer of crushed stone will add proper drainage, as well as create a barrier between your slab and the ground.
What is a good moisture barrier for concrete floor?
Polyguard – The Best Prevention Against Water and Vapor Transmission Through Concrete Slabs on Grade. Polyguard Underseal Underslab Membrane and Polyguard TERM Floor Underlayment Barrier.
How do you install a 6 mil vapor barrier on concrete?
To properly install a vapor barrier into your basement's concrete floor, follow the steps below:Choose a vapor barrier/retarder.Remove any debris and dirt.Unroll and cut vapor barrier.Apply adhesives on the edges.Adhere the vapor barrier to the wall.Seal the vapor barrier seams.Fix any damage.
How do you install a vapor barrier under a concrete slab?
0:555:23STEGO® WRAP | How to Install an Under-Slab Vapor Barrier - YouTubeYouTubeStart of suggested clipEnd of suggested clipIt should completely cover the placement area all joints and seams should be overlap at least 6MoreIt should completely cover the placement area all joints and seams should be overlap at least 6 inches and sealed using stego tape or stay go creek long. Stay go tape provides the most efficient.
What kind of plastic do you put under concrete?
The most commonly used vapor barrier under concrete slabs is polyethylene (poly) plastic sheeting with a thickness of 10 mil or 15 mil. All Americover Vapor Barriers are composed of virgin polyolefin resins and offered in 10 mil, 15 mil, and 20 mil.
Why do they put Styrofoam under concrete?
They reduce the effects of soil movement, decrease the amount of concrete required, and have thermal insular properties making them a cost effective component for any home, building or complex. In traditional slabs, the bottom of the slab uses footings based on concrete beams which require extensive digging.
Do I need a vapor barrier under my concrete slab?
Water vapor will always move from a high relative humidity environment below the building into an area of low relative humidity – even through concrete. That’s why nearly every expert in the concrete industry recommends a below – slab vapor barrier to stop the vapor drive of water upward and into your building envelope.
Do you need rebar for 4 inch slab?
No, you do not need rebar for a 4 – inch slab of concrete on grade. A 4 – inch -thick slab cast on the ground and in permanent contact with it will float and rebar is not required. Rebar is recommended on concrete measuring 5 – 6 inches thick.
What kind of insulation goes under slab?
Two of the rigid foam insulations most commonly used below grade and under slabs are expanded polystyrene ( EPS) and extruded polystyrene ( XPS ). Although both are closed cell insulations, they perform very differently over the long term.
Is Tyvek a vapor barrier?
No, DuPont ™ Tyvek® is not a vapor barrier. It is made with unique material science to keep air and bulk water out while allowing moisture vapor inside walls to escape.
Should you put plastic under concrete?
Vapor barriers are used because while fresh concrete is poured wet, it’s not supposed to stay that way. It needs to dry and then stay dry to avoid flooring problems. This is why a vapor barrier under concrete is essential.
What Kind of Vapor Barrier Can I Use Under Concrete?
To be safe, a vapor retarder placed beneath the concrete to prevent moisture movement must have a Class 1 overall score and permeability of 0.06 Perms IMP or lower, according to the code. A Perms IMP score of 0.059, which is roughly 0.06 Perms IMP. Polyethylene was not permitted to be thinner than six mils in 2018.
What Are the Characteristics of a Plastic Barrier Used in Construction?
A vapor or plastic barrier is a layer that prevents or slows the entry of moisture vapor. A moisture or vapor retarder is another name for it. A vapor barrier or retarder must have a permeance of 0.1 Perms IMP or less to be considered “impermeable.” Real moisture or vapor barriers have a permeance of 0.00 Perms, which implies nothing can get through.
Do You Need Plastic Under Concrete Driveway?
A critical choice is whether to install a vapor barrier underneath the concrete driveway or not .
Why use plastic under slab?
Thanks! Plastic is a moisture barrier generally to stop ingress from beneath the slab. If this is outdoor in an exposed area it probably doesn't matter. I'd probably use plastic if the area is moist with little sun, just to alleviate any algae growth. Click to see full answer. Similarly, you may ask, do you need a vapor barrier under ...
Why do concrete slabs need poly?
Concrete contractors learned that a layer of poly helps to keep a slab dry, because it stops upward vapor diffusion from the soil. The foam layer isolates the room-temperature slab from the cold soil under the slab.
Why do we need a vapor barrier under concrete?
Vapor barriers are used because while fresh concrete is poured wet, it's not supposed to stay that way. It needs to dry and then stay dry to avoid flooring problems. This is why a vapor barrier under concrete is essential.
How much permeance does concrete have?
Standard concrete has the permeance of 3.2 Perms IMP which will allow ground moisture to wick up through it. A layer of 6-mil poly has the permeability of 0.059 Perms IMP and 10-mil poly 0.3 Perms IMP. The thicker the poly, the better and more durable the barrier. It is interesting to note, though, that 1 mil aluminum foil has the permeance of 0.00 Perms IMP.
What is the minimum vapor barrier required for concrete?
Concrete slabs that will be within heated structures must have a vapor barrier. Subsection R506.2.3 of the 2018 IRC states that a minimum of 6-mil polyethylene vapor retarder be used between the concrete and the base course or prepared ground. It also requires seams or joints in the barrier to have a minimum 6” overlap sealed with compatible material.
How thick should a moisture barrier be?
A moisture retarding barrier needs to have a permeance of 0.06 Perms or less. It should also be at least 6 one-thousandths of an inch thick to withstand punctures and tears during the concrete pour. The IRC identifies 6-mil polyethylene as the minimum acceptable barrier for under concrete, and the ACI states 10-mil poly as their minimum recommended choice.
What is the best material to use for vapor barrier?
A common practice is to use a thin layer of polyethylene (plastic) sheeting as a vapor barrier. The permeable nature of concrete allows ground moisture to penetrate upward to flooring or anything in contact with the concrete.
How far should vapor membrane go up walls?
It should be the last layer before the concrete – even on top of any rigid foam insulation. The barrier should go 3” to 4” up any walls and be sealed to the foundation concrete with appropriate binders, or extend 4” to 6” beyond the formed framework.
Why do you need a vapor barrier on a concrete floor?
A vapor barrier under the concrete decreases the amount of moisture that can wick through the concrete and into the living space.
Where should moisture barrier be placed for concrete?
When preparing for a concrete pour, the vapor retarding barrier should be placed directly below where the concrete will be poured.
Why put plastic under concrete?
One contractor says to put plastic under the concrete, it prevents moisture from coming up into the concrete. The other contractor says NO Way, No plastic, holds the water in the concrete during the drying process and can leave webbing like visual affect in finish of concrete. What is correct?
Why use vapor barrier on concrete?
The main reason for vapor barrieers to be used in concrete applications is for things like a basement floor. For example, a floor that will be tiled over, sub floor glued, etc. The moisture coming up from the concrete can weaken the adhesives and cause loose tiles, etc.#N#The drawback to these vapor barriers again is excessive moisture in the curing process. If the mix retains too much moisture, it can lead to delamination of the concrete. I dont think you want the surface of your floor to blister and peel away. There's a lot of variables here, and in theory the vapor barriers sound good. But, check into it toroughly. Ive been doing concrete and been around concrete for a long time, and Ive never seen anyone put plastic under a garage slab around here.
Does plastic hold water?
If your contractor is good with concrete then he should have no problems with the finish with plastic. It will hold a little more water, but nothing thats major.
Can you put poly on concrete after tamping?
Depends on soil conditions. If the soil is sandy type or similar, after tamping the floor area I would put a layer of poly. If you don`t, it will suck the water from the pour and cause problems. There are times in hot weather where wetting the concrete is needed to slow the curing process.
Is 5" mesh a good thickness?
5" is plenty of thickness as long as the sub- grade is right and there is mesh.
Does concrete need water?
Too much water in the mix dilutes the concrete, and will reduce the strength, possibly causing cracks, peeling, surface ships etc. I would not worry about moisture coming up from the ground damging the concrete. Once its cured, the moisture wont hurt it. Concrete is used on sea walls, piers, drains, sewers, etc. Most important is to get a good mix, some steel in it, 4" minimum on thickness, good weather for the pour, and a good Finisher.
Why is 6 mil visqueen used under concrete?
Recently, though, research has shown that the old traditional layer of 6-mil Visqueen (polyethylene plastic) under the slab is seldom effective for two main reasons: Although it may seem water-tight, this grade of material allows a lot of water vapor to pass through. 6-mil plastic often gets damaged during placement of reinforcement and concrete, ...
What is the minimum thickness of a vapor barrier?
ACI 302.1, Guide for Concrete Floor and Slab Construction, states that the minimum thickness of an effective vapor barrier is 10 mils. This was verfied by some field studies conducted by Concrete Construction magazine. Thinner plastic can't stand up to the abuse of construction. ASTM E-1745 specifies minimum values for tensile strength and puncture resistance that increase from Class C to Class A.
How much does a 15 mil vapor barrier cost?
Typical 8-mil polyethylene sheeting costs 5 to 7 cents per square foot. A 15-mil vapor barrier can be about 25 cents per square foot. Sure, that's an increase, but it's better than a damp, discolored slab.
How to make sure slab is dry?
Bottom line: If you want to make sure your slab on ground gets dry and stays dry, use a vapor barrier.
Why are basement floors like concrete?
One of the reasons those old basement floors were like that was because they had no vapor barrier beneath them, leaving an easy path for water vapor from the soil to migrate into the slab, ...
Is a 10 mil barrier good for residential construction?
A 10-mil barrier is probably OK for residential construction if you're careful not to puncture it during construction.
Can 6-mil plastic be damaged?
6-mil plastic often gets damaged during placement of reinforcement and concrete, creating holes that can let a considerable amount of water vapor into the slab. True vapor barriers allow little water vapor to penetrate. W.
