GROIN VAULT Square & Rectangle Room Layout
A s s e m b ly and I nst al l at i on In str u ction s
GROIN VAU LT
A Groin Vault is formed by intersecting two barrel vaults, or
curved ceilings. A groin is the curved intersection of the two
vaults. Vault intersections can be an inside or outside groin,
both use the same process to create a template.
Armstrong drywall grid
system cross tee
RC2
Armstrong drywall grid
system main beam
notched & spliced
gypsum board
Armstrong drywall grid
system cross tee
Armstrong drywall grid
system main beam
notched & spliced
SQUA RE ROOM L AYOU T
G
This is the simplest type of groin ceiling to layout and install.
The four primary vaults are the same, and the groin will be an
elliptical vault running diagonally corner-to-corner. This will
require two templates – one for the primary vault and one for
the groin. Groin template must be to scale, full size, best done
on the floor directly below the vaults to use as an installation
reference.
A
A
D
E
D
F
B
B
C
C
Step 4: Layout line F - G beginning at point F, running through
point E, equal in length to side A - B. Point G represents the
top of the vault, and line F - G represents the centerline of
the vault.
Step 1: Lay out the square A, B, C and D to represent the
dimensions of the room.
G
A
A
D
D
E
E
F
B
B
C
C
Step 5: Using point E as the center point, and dimension
E - Aas the radius, form the primary vault from points A to D.
Step 2: Determine the midpoint of line A - D and label E.
This is the radius point for the primary vaults.
G
A
D
A
E
D
E
F
90.0°
B
H
C
B
Step 3: Layout diagonal lines A - C andB - D – these are
thegroin lines. Label the intersection of these lines F.
F
C
Step 6: Use the rise of the primary vault (E - G) and locate the
rise of the groin vault (F - H).
2
G
G
A 1 2 3 4 5 6
1
A 1 2 3 4 5 6
D
1
E
2
3
4
5
2
3
5
F
B
C
Step 7: Run lines parallel to line F - G at one foot intervals
beginning at point E and moving towards point A. Number
the points where these lines intersect the diagonal (A - C)
beginning at point A.
C
Step 10: Mirror points created in Step 8 along line F - C.
G
A 1 2 3 4 5 6
G
1
A 1 2 3 4 5 6
D
2
D
E
3
E
3
F
6
H
B
2
4
6
H
1
D
E
4
5
6
F
4
5
F
6
H
B
C
H
B
Step 11: Form the groin vault by connecting the points
created in Steps 9 and 10.
C
Step 12: Curves A, G, D and A, H, C can be used to create
templates to construct faceted main beams.
Step 8: Mark and run lines perpendicular to line A - C at each
of the points created in Step 7.
G
A 1 2 3 4 5 6
1
2
D
E
3
4
5
6
F
90.0°
H
B
C
Step 9: Transfer length of each line created in Step 7 to
corresponding lines created in Step 8. This will create curve
points of the groin vault.
3
REC TA N GU LAR ROOM L AYO UT
Layout for rectangular rooms is similar to that for square
rooms,except that three templates will be required: the primary
vault for the short walls, a true radius vault, the secondary vault
for the long walls, this will be an elliptical arch, and the groin
vault running diagonally corner to corner. The rise for each
vault will be the same dimension.
Main Beam
Cross Tee
Typical
Gr
oin
Main Beam
oin
Gr
C
oin
Gr
C
Gr
oin
C
Main Beam
C
Cross Tee
Typical
Main Beam
11
1'-4 "
16
Groin Main Beam
1
–"
1'-114
5
–"
3'-118
1
3'-10 –"
2
1
3'-8 – "
2
9
3'-5 – "
16
1
–"
3'-12
11
1'-4 "
16
3
–"
2'-7 4
1
–"
1'-114
3
–"
2'-7 4
1
–"
3'-12
9
3'-5 – "
16
1
3'-8 – "
2
1
3'-10 –"
2
4'
1
1'-0 – " TYP
16
5
–"
3'-118
8'
4'
4'
9
–"
1 3'-8 1
– " 3'-516
5
–"
– " 3'-10 2
2
3'-118
14'
M ORE IN FORM AT I O N
For more information, or for an Armstrong representative, call 1 877 ARMSTRONG.
For complete technical information, detail drawings, CAD design assistance, installation information,
and many other technical services, call TechLineSM at 1 877 ARMSTRONG or FAX 1 800 572 TECH.
For the latest product selection and specification data, visit armstrong.com/ceilings.
U.S. Patents Pending, including US Publication No. 2004/0182022.
All trademarks used herein are the property of AWI Licensing Company and/or its affiliates
© 2015 AWI Licensing Company • Printed in the United States of America
BPLA-297444-315
1
–"
3'-12
3
–"
2'-7 4
1
–"
1'-114
11
1'-4 "
16