Can someone help me figure out type of drywall I need to buy to cover wooden beams in picture?

1st picture gives you view from the far. In 2nd picture, I have zoomed in the area inside red rectangle in 1st picture.

In 2nd picture, C is wood. B is thick drywall but I am not sure about what A is. Is it part of drywall ? I have never seen anything like this. I need to buy similar piece of drywall and cover that wooden beams.

1st picture:

2nd picture

3rd picture

4th picture

5th picturw

3rd picture shows cross section view of all layers.

4th and 5th picture shows how piece of layer A look like.

  • 1
    Measure the overall thickness and that is your guide to what drywall you are going to buy. Thats all.
    – noybman
    Dec 15, 2019 at 20:03
  • When you say you intend to "cover that wooden beam", do you mean to say that you mean to drywall over the entire beam span, on the bottom, shown as "C"? Dec 15, 2019 at 20:24
  • Noybman - I tried finding drywall with similar thickness but I couldn't find. Thats why I want to know if A and B are part of one thing or applied separetly. Jimmy - yes, I want to cover entire beam span with drywall. Infact that is how it was before I had to open it (to dry ) because of water damage from upstairs. Dec 15, 2019 at 20:40
  • why don't you slide a boxcutter blade between A and B to determine if they are separate layers
    – jsotola
    Dec 15, 2019 at 21:22
  • 1
    A in the picture is jointing compound, who ever did this used the jointing compound to fill in the gaps between the corner bead to give a nice square edge. You will find more jointing compound used in DIY projects than professionals use as professional drywall contractors have a lot more experience in getting tight corners and don't like wasting material. If you are doing this yourself consider using a corner bead tool to get a nice tight corner and you will use less jointing compound. Dec 16, 2019 at 15:26

1 Answer 1


You can wrap the beam with a number of different sheet materials. You're not limited to drywall - but that will work too. The key is to select a material closest to the existing wall board thickness. You are trying to match that thickness.The finish mud and tape will stick to plywood (for example) as well as paper covered gypsum sheets. Drywall is commonly used because it is inexpensive, not because it has any desirable structural characteristics.

  • 1
    Drywall does sometimes contribute desirable characteristics, it can provide fire rated protection where required (e.g. 5/8" Type-X gives 1 hr. fire rating). Also, it's a good insulator, good sound blocker, it's nice and flat and easy to paint, it is easily repairable, ect... Dec 16, 2019 at 5:23

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