Basement drywall questions
#1
03-14-13, 04:10 PM
Basement drywall questions
Hi everyone....
I'm looking to drywall my basement and have a few general questions. Any help and advice is greatly appreciated. I'm fairly good with home projects though have not done a lot of larger drywall projects. Most of my experience to date has been patching and refinishing.
My basement is currently partially finished. We are removing the wood paneling on the walls and finishing the ceiling.
1. Most places I've read say drywall the ceiling first. However... i'd like to do the walls first as it will allow me to allow the kids into the basement sooner. This is probably a 3-4 week project for me. What are the disadvantages for doing the walls first? Am I going to be causing any major issues?
2. My walls are framed out w/2x4's. What thickness drywall should I be using?
3. Should I be using any special anti-moisture or mold resistant drywall? My basement is exceedingly dry with no water problems or infiltration. My house is 25+ years old so any water issues would have already appeared if there were going to. My basement is also only about 1/2 underground which helps.
4. Any special tricks or advice from other weekend warriors who have finished their basement?
Thanks again!!!
Scott
I'm looking to drywall my basement and have a few general questions. Any help and advice is greatly appreciated. I'm fairly good with home projects though have not done a lot of larger drywall projects. Most of my experience to date has been patching and refinishing.
My basement is currently partially finished. We are removing the wood paneling on the walls and finishing the ceiling.
1. Most places I've read say drywall the ceiling first. However... i'd like to do the walls first as it will allow me to allow the kids into the basement sooner. This is probably a 3-4 week project for me. What are the disadvantages for doing the walls first? Am I going to be causing any major issues?
2. My walls are framed out w/2x4's. What thickness drywall should I be using?
3. Should I be using any special anti-moisture or mold resistant drywall? My basement is exceedingly dry with no water problems or infiltration. My house is 25+ years old so any water issues would have already appeared if there were going to. My basement is also only about 1/2 underground which helps.
4. Any special tricks or advice from other weekend warriors who have finished their basement?
Thanks again!!!
Scott
#2
03-14-13, 05:14 PM
i'd like to do the walls first as it will allow me to allow the kids into the basement sooner. This is probably a 3-4 week project for me. What are the disadvantages for doing the walls first? Am I going to be causing any major issues?
Have you thought of installing a suspended ceiling inside the finished walls?
My walls are framed out w/2x4's. What thickness drywall should I be using?
Should I be using any special anti-moisture or mold resistant drywall?
My basement is also only about 1/2 underground which helps.
#3
03-14-13, 05:14 PM
Welcome to the forums!
1) Drywalling the ceiling first is normal. That way you can jam your wall sheets to the ceiling, obtaining a smooth corner to finish. The wall sheets also help to hold the edge of the ceiling straight.
2) 1/2" sheetrock and 1 5/8 screws would suffice
3) If you have insulation in the stud bays, cover the surface of the walls with a 6 mil vapor barrier, then apply your sheetrock.
4) If you apply your wall sheetrock sideways, install your top half first so you can get the smooth corner at the ceiling, then install the bottom half. You may have a gap at the bottom, but that is to keep it off the floor to prevent wicking. Your base molding will cover it.
1) Drywalling the ceiling first is normal. That way you can jam your wall sheets to the ceiling, obtaining a smooth corner to finish. The wall sheets also help to hold the edge of the ceiling straight.
2) 1/2" sheetrock and 1 5/8 screws would suffice
3) If you have insulation in the stud bays, cover the surface of the walls with a 6 mil vapor barrier, then apply your sheetrock.
4) If you apply your wall sheetrock sideways, install your top half first so you can get the smooth corner at the ceiling, then install the bottom half. You may have a gap at the bottom, but that is to keep it off the floor to prevent wicking. Your base molding will cover it.
#4
03-14-13, 07:07 PM
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Don't insulate the parts that are below grade.
I was wondering Nashkat1 why not? I think I would. The dirt behind and therefore the wall itself stays pretty cold.
#5
03-14-13, 07:15 PM
But it stays the same temperature year 'round. You would be insulating it to keep it the same temperature. Insulation won't change the temperature of the concrete. It's probably in the 50- 70 degree range, anyway, (depending on frost line) which is cold to the touch. Geothermal heating/cooling uses the same theory.
#6
03-14-13, 07:44 PM
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but the insulation would insulate the room from the 45 degree dirt same as above its insulating from 45 degree (or whatever) outside air
#7
03-16-13, 01:12 PM
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Larry may live in Zone 2, where basement insulation is not required (must be nice :-) Chapter 11 - Energy Efficiency
But for anyone else living in Zones 3-8, basement insulation is required per building codes: Chapter 11 - Energy Efficiency
Notice Zone 4 includes Maryland, the OP; that should insulate below grade because of the groundwater temperature that remains cold down to the “frost line”, 16-23” deep for the OP; http://www.soundfootings.com/pdf/US_...t_DepthAVG.pdf
Well, those are just averages, it can get worse at different time of the year, today in MD, is 37*F ground temp. and close to that 2’ down against the concrete wall, except the basement is warming the wall (which is why it looks dry all the time, moisture is evaporating away as quickly as it forms, soon to change with insulation/drywall blocking the room air currents) and the soil right now; US Soil Temperatures | Smith Fertilizer and Grain
Problem is, once you insulate with fibrous batt that is vapor permeable, any moisture can condense on the cold concrete wall. The batt does nothing to isolate the wall temperature from the cavity temperature (as rigid foamboard or SPF does). This can run down the wall to pool at the bottom plate; wicking up to the framing (with a plastic vapor barrier next to the drywall where does it dry to?) to rot the framing and degrade the insulation if in contact with the concrete wall which just makes matters worse; with lower temps comes lower dew-points for condensation. So the wet R-13 is at R-5 now: ARCHIVED - Controlling the Transfer of Heat, Air and Moisture through the Building Envelope - IRC - NRC-CNRC
When the concrete wall temperature lowers, the Relative Humidity goes up, correspondingly. E.g. The 37*F, at 70* basement air, has a 31%RH dew-point, but with 1’ of XPS foamboard, that would raise the RH to 42%. More on foamboard raising the dew-point temps of the concrete wall (or inside face of sheathing/foamboard); BSD-163: Controlling Cold-Weather Condensation Using Insulation — Building Science Information Using the average of the 3 months low temps for your specific city, I could figure the RH for you… if needed.
You could easily get by with less f.b. unless right on the border of Zone 5; IRC FAQ: Insulating Sheathing Vapor Retarder Requirements — Building Science Information
Below the frost line (about 6’ below-grade), basement wall temps are stabilized at 50-60*F in most of U.S., but some areas are colder/deeper. 6’ down the temps are 10-11*F warmer than ambient air/surface water temps. Which is why most Geo-thermal systems are 6’ down, minimum. Average Shallow GroundWater Temperatures | Ecosystems Research | US EPA So MD is about 49*F +10*F = 59-60*F temperature of basement 6’ below-grade. Since yours is less deep and you may be located more South in the state, f.b. is mainly to keep the interior moisture from condensing on the concrete wall rather than its insulating properties. A thinner f.b. may work, especially if controlling the interior humidity during winter months. This is why each wall is figured per location.
Gary
But for anyone else living in Zones 3-8, basement insulation is required per building codes: Chapter 11 - Energy Efficiency
Notice Zone 4 includes Maryland, the OP; that should insulate below grade because of the groundwater temperature that remains cold down to the “frost line”, 16-23” deep for the OP; http://www.soundfootings.com/pdf/US_...t_DepthAVG.pdf
Well, those are just averages, it can get worse at different time of the year, today in MD, is 37*F ground temp. and close to that 2’ down against the concrete wall, except the basement is warming the wall (which is why it looks dry all the time, moisture is evaporating away as quickly as it forms, soon to change with insulation/drywall blocking the room air currents) and the soil right now; US Soil Temperatures | Smith Fertilizer and Grain
Problem is, once you insulate with fibrous batt that is vapor permeable, any moisture can condense on the cold concrete wall. The batt does nothing to isolate the wall temperature from the cavity temperature (as rigid foamboard or SPF does). This can run down the wall to pool at the bottom plate; wicking up to the framing (with a plastic vapor barrier next to the drywall where does it dry to?) to rot the framing and degrade the insulation if in contact with the concrete wall which just makes matters worse; with lower temps comes lower dew-points for condensation. So the wet R-13 is at R-5 now: ARCHIVED - Controlling the Transfer of Heat, Air and Moisture through the Building Envelope - IRC - NRC-CNRC
When the concrete wall temperature lowers, the Relative Humidity goes up, correspondingly. E.g. The 37*F, at 70* basement air, has a 31%RH dew-point, but with 1’ of XPS foamboard, that would raise the RH to 42%. More on foamboard raising the dew-point temps of the concrete wall (or inside face of sheathing/foamboard); BSD-163: Controlling Cold-Weather Condensation Using Insulation — Building Science Information Using the average of the 3 months low temps for your specific city, I could figure the RH for you… if needed.
You could easily get by with less f.b. unless right on the border of Zone 5; IRC FAQ: Insulating Sheathing Vapor Retarder Requirements — Building Science Information
Below the frost line (about 6’ below-grade), basement wall temps are stabilized at 50-60*F in most of U.S., but some areas are colder/deeper. 6’ down the temps are 10-11*F warmer than ambient air/surface water temps. Which is why most Geo-thermal systems are 6’ down, minimum. Average Shallow GroundWater Temperatures | Ecosystems Research | US EPA So MD is about 49*F +10*F = 59-60*F temperature of basement 6’ below-grade. Since yours is less deep and you may be located more South in the state, f.b. is mainly to keep the interior moisture from condensing on the concrete wall rather than its insulating properties. A thinner f.b. may work, especially if controlling the interior humidity during winter months. This is why each wall is figured per location.
Gary
