Foundations are the one part of a building you will never see again after backfilling, so any waterproofing mistake shows up years later as rising damp in walls, peeling paint and tiles, or, at worst, corroded rebar and deteriorating concrete. This guide explains how to do bitumen foundation waterproofing correctly with Al-Madina AL-70.
Why waterproof footings and foundations?
Soil in many parts of Saudi Arabia contains salts and sulphates, and groundwater is sometimes close to the surface. Concrete is porous and absorbs moisture and salts over time, which leads to:
- Corrosion of reinforcing steel and spalling of the surrounding concrete.
- Rising damp into walls and floors by capillary action.
- Weakening of concrete through sulphate attack.
A bituminous coating seals the concrete pores and separates the structure from the soil, protecting it for the life of the building.
What is AL-70 cold bitumen?
Al-Madina AL-70 is a water-based bitumen emulsion made in Saudi Arabia. It dries into a flexible black membrane that adheres strongly to concrete. Key features:
- Cold applied: no heating, faster and safer on site, non-flammable.
- Salt resistant: protects concrete and rebar from soil salts and sulphates.
- Dry or slightly damp substrates: suits real site conditions.
- Easy to apply: by brush or roller.
What needs bitumen waterproofing?
- Reinforced concrete footings: all sides and the top face.
- Column necks up to above finished backfill level.
- Ground beams on every face in contact with soil.
- Retaining walls and basement walls (external face).
- Underground tanks (external face).
- As a damp-proof layer under ground-floor slabs and bathrooms.
Step-by-step application
1. Strip formwork and fix defects
Remove protruding nails and tie wires, knock off sharp edges and repair honeycombing with repair mortar before waterproofing.
2. Clean the surface
The concrete must be completely free of dust, soil and oil, including formwork release oil. AL-70 can go on dry or slightly damp concrete, but not on standing water.
3. Primer coat
Dilute AL-70 with 20% clean water and brush it on as a primer. It penetrates the pores and prepares the surface for the following coats.
4. Undiluted coats
Once the primer is dry, apply one or two more coats of undiluted AL-70 by brush or roller, each at right angles to the previous one, with special attention to edges and corners.
5. Protect before backfilling
Do not backfill until the coating is fully dry. Good site practice is to wrap footings with polyethylene sheet or protection board so that stones do not puncture the membrane during compaction.
How many coats do footings need?
Per the product instructions: one primer coat diluted 20% with water, then one or two undiluted coats. In wet or saline soil, or with a high water table, we recommend two full coats after the primer (three in total).
Common mistakes
- Coating the sides only and leaving the top of the footing or the column neck bare.
- Applying over dust or release oil, so the coating peels off.
- Backfilling before the coating dries, or with sharp stones.
- Stopping the column-neck coating below backfill level.
- A single coat in saline soil.
Related reading: Acrylic Roof Waterproofing: How to Apply Al-Madina Roof 200 & Shield Roof 260 (Coverage per m²) · Concrete Bonding Agent for Old to New Concrete: Uses of Al-Madina Bond & Bond Plus in Plaster and Repairs
FAQ
Is cold bitumen as effective as hot bitumen?
Cold bitumen emulsion gives a flexible, well-bonded membrane, and is easier and safer to apply because it needs no heating and does not burn. It is now the common choice for footings and ground beams in residential buildings.
Can I apply it on damp concrete?
Yes, AL-70 can be applied on slightly damp concrete, as long as there is no standing water.
Can I use AL-70 in bathrooms?
It works as a damp-proof layer under floors. For bathrooms under tiles, a dedicated liquid rubber such as Al-Madina Proof 220 is better.
Order foundation waterproofing from Top Building
Al-Madina AL-70 bitumen foundation insulator is available at Top Building with delivery across Saudi Arabia. Send us the number and sizes of your footings on WhatsApp and we will help you calculate the quantity.
