DomCast Metals supplies HDPE adjustment units for raising maintenance holes, catch basins and valve chambers to finished grade. They are also called adjustment rings, riser rings or grade rings. The catalog covers square and round units, sloped units for crowned road surfaces, and thin final-grade shims.
Ontario tender documents usually call these adjustment units rather than rings. Match the wording in your contract documents when you order, and confirm sizes against the structure at quote time. Canadian-owned supplier serving the waterworks market for 80+ years.
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Products (28 SKUs)
- 24" X 24" Square 1 1/4" · LD2424F125
- 24" X 24" Square 1 1/2" · LD2424F150
- 24" X 24" Square 2" · LD2424F200
- 24" X 24" Square 2 3/4" · LD2424F275
- 24" X 24" 1 1/4" to 2 3/4" 6% Slope · LD2424S125
- 24" X 24" 3/4" to 1 1/2" · LD2424S150
- 24" X 24" 2" to 2 3/4" 3% Slope · LD2424S275
- Final Grade 24"X24" 1/4" Square · LDSP2424FS-025
- 24" x 1 1/4" Manhole Adjustment Unit · LD24R125
- 24" x 1 1/2" Manhole Adjustment Unit · LD24R150
- 24" x 2" Manhole Adjustment Unit · LD24R200
- 24" x 4" Manhole Adjustment Unit · LD24R400
- 24" x 3/4" to 1 1/2" Manhole Adjustment Unit · LD24S150
- 27" x 1 1/4" Manhole Adjustment Ring · LD27R125
- 27" x 1 1/2" Manhole Adjustment Ring · LD27R150
- 27" x 2" Manhole Adjustment Ring · LD27R200
- 27" x 4" Manhole Adjustment Ring · LD27R400
- 27" x 3/4" to 1 1/2" Manhole Adjustment Ring · LD27S150
- 30" x 1 1/2" Manhole Adjustment Ring · LD30F150
- 30" x 2 1/4" Manhole Adjustment Ring · LD30F225
- 30" x 4" Manhole Adjustment Ring · LD30F400
- 30" x 1 1/2" to 2 1/4" Manhole Adjustment Ring · LD30S225
- 34" x 2" Manhole Adjustment Ring · LD34F200
- 24" x 1/4" Final Grade Manhole Adjustment Unit · LDSP24FS025
- 27" x 1/4" Final Grade Manhole Adjustment Unit · LDSP27FS025
- 30" x 1/4" Final Grade Manhole Adjustment Unit · LDSP30FS025
- Butyl Sealant Caulking Large 825ml Tube · BUTYL825
- Butyl Sealant Caulking Small 300ml Tube · BUTYL300
Common questions
What does Ontario call an adjustment ring?
OPSS terminology is adjustment unit. OPSS 408 lists three material specifications for them: precast concrete units to OPSS 1351, rubber units to OPSS 1853, and high density polyethylene (HDPE) and expanded polystyrene (EPS) units to OPSS 1854. DomCast supplies HDPE units. Source: OPSS.PROV 408, clause 408.05.01.
How many adjustment units are allowed on one structure?
OPSS.PROV 408 states there shall be a minimum of one adjustment unit on the top of the drainage structure, and no more than three are permitted without prior written approval from the Contract Administrator. Always verify against the contract documents governing your project, which may differ from the provincial specification.
What is the difference between an adjustment unit and a lift ring?
OPSS.PROV 408 defines lift rings as circular and rectangular pre-fabricated metal or high density polyethylene units used to adjust the elevation of the grates and covers only, inserted between the frame and the grate or cover. Adjustment units sit under the frame and raise the structure itself.
Do you stock sloped units for crowned roads?
Yes. The catalog includes sloped units alongside flat units. The slope and size are stated in each product name; confirm the required slope against the road cross-section at quote time.