What is a bridge washer?

Malleable Iron Washers
Import (left), Domestic (right)

This is a term that is frequently used across the industry. More often than not, “bridge washers” will refer to cast iron malleable iron washers. These washers are typically used in dock and wood construction. Malleable iron washers are specifically designed to prevent bolt heads and nuts from pulling into the wood. Detailers will also specify them in plans as “malleable washers”, “MI bridge washers”, or “MIW”. They will often state the bridge washers as malleable cast iron and conforming to ASTM A47.

If you have any questions about malleable washers, please give us a call and one of our experienced estimators will be more than happy to help out.

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2 comments

    What are the sizes (dia) and the cost import vs. domestic ?
    I’m building another house,for myself, and all the heavy timber connections top have bridge washers.

    @Denzil- It is hard to give you specific estimates for a general question. The cost differences will vary wildly depending on the sizes and quantities. In some cases, if both are readily available, the costs might be double, whereas if you end up needing something that isn’t off the shelf and is a special, the cost difference could be several thousand percent.

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