How do poured concrete and block foundation walls differ?
Poured walls are shaped by forms that hold wet concrete, while block walls are built one row at a time with mortar. This changes what arrives on site and the work the crew performs. A poured-wall crew needs to position forms and place concrete; a block-wall crew needs masonry materials and room to build with them.
The surface left by that work also affects preparation for moisture protection. A damp-proof coating limits moisture passing through a wall, but it isn't complete waterproofing. The table follows Pacific Northwest National Laboratory (PNNL) guidance on preparing the two surfaces.
| Poured concrete walls | Concrete block walls |
|---|---|
| How the wall is built | |
| Concrete hardens on site inside forms, the molds that give the wall its shape. | Concrete masonry units (CMUs) are individual concrete blocks laid in rows with mortar between them. |
| Details to identify in the design | |
| Ask the designer to identify the wall dimensions, connections, steel reinforcement and concrete needed. | Ask the designer to identify the wall dimensions, connections, steel, blocks, mortar and grout. Grout fills designated spaces inside the blocks. |
| Delivery and installation questions | |
| How will the crew bring in the forms and place concrete at the wall location? | Where will blocks and other materials be stored, and who will carry out the masonry work? |
| Preparation for moisture protection | |
| PNNL describes applying a damp-proof coating directly to the concrete surface. | PNNL describes a smoothing coat of mortar, called parging, before damp-proofing rough masonry surfaces. |
Neither material name tells you whether a wall design suits your home. The designer has to account for the soil, the loads from the building and the site. This is why a detailed reinforced poured-wall plan and a vague offer for “block walls” aren't enough to compare: the second offer still leaves the actual design unknown.
Do poured concrete or block walls make a basement waterproof?
Neither untreated poured concrete nor untreated block makes a basement waterproof. Concrete products are porous, so the wall material is only one part of keeping moisture out. Surface protection and drainage have to work with it.
For example, a quote that names a damp-proof coating hasn't necessarily included a complete waterproofing system or the associated drainage work. PNNL distinguishes those functions. A useful proposal describes the protection, surface preparation and drainage together, making clear which work each contractor includes. “Waterproof foundation” on its own doesn't give you that information.
What should you include when comparing foundation wall costs?
Include preparation, wall construction, moisture protection and connections to the building when comparing foundation-wall costs. The price of concrete or blocks is only part of the job. Excavation, footings and drainage may also be included in the quote, so their prices need to be separated from the wall itself.
Footings are the supporting bases beneath foundation walls. If one proposal includes them and another prices only the walls above them, the totals cover different jobs. The same problem comes up when one price includes moisture protection and another leaves it to a separate contractor. An itemized quote makes these gaps visible.
For the wall construction, poured-wall pricing should cover forms and concrete placement; block-wall pricing should cover masonry labor, reinforcement and any specified filling of block spaces. The wall lengths, heights, openings and design requirements also need to match. A lower price following a design change may buy less or different work, rather than the same work for less.
The concrete foundation cost guide helps with whole-project budgeting. Its slab, crawl-space and basement ranges use the building's ground-level area, so they cannot be applied as prices per square foot of poured or block wall.
Who should you contact for foundation wall quotes?
Contact a foundation contractor who installs the wall system in your plans; block construction may require a masonry contractor. The drawings give them something specific to price, rather than leaving each company to assume a different wall.
If you are still deciding on the wall system, include that in your request along with the available site information and intended basement or crawl-space use. Someone will need to provide the design before a final construction price is meaningful. Contractors for Concrete helps you prepare the request and seek contractor options; we don't design the foundation or guarantee a match.
Prepare a foundation contractor request