---
product_id: 5587474
title: "M-D Building Products - Versatile Gray Foam Backer Rod - Essential Caulk Saver for Sealing Concrete Gaps, Expansion Joints, and Crack Filling, 3/8 by 20 Feet (71464)"
brand: "m-d building products"
price: "$33"
currency: NZD
in_stock: true
reviews_count: 13
category: "M D Building Products"
url: https://www.desertcart.nz/products/5587474-m-d-building-products-versatile-gray-foam-backer-rod-essential
store_origin: NZ
region: New Zealand
---

# Easily trimmed to size Weather-resistant & waterproof 3/8 inch diameter for medium gaps M-D Building Products - Versatile Gray Foam Backer Rod - Essential Caulk Saver for Sealing Concrete Gaps, Expansion Joints, and Crack Filling, 3/8 by 20 Feet (71464)

**Brand:** m-d building products
**Price:** $33
**Availability:** ✅ In Stock

## Summary

> 🔧 Seal Smart, Save Big: The Ultimate Caulk Companion You Can't Afford to Miss!

## Quick Answers

- **What is this?** M-D Building Products - Versatile Gray Foam Backer Rod - Essential Caulk Saver for Sealing Concrete Gaps, Expansion Joints, and Crack Filling, 3/8 by 20 Feet (71464) by m-d building products
- **How much does it cost?** $33 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.nz](https://www.desertcart.nz/products/5587474-m-d-building-products-versatile-gray-foam-backer-rod-essential)

## Best For

- m-d building products enthusiasts

## Why This Product

- Trusted m-d building products brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Multi-Use Home Armor:** Ideal for sealing concrete, expansion joints, windows, doors, and even insulating irregular spaces for enhanced comfort.
- • **Built to Brave the Elements:** Crafted from closed-cell polyethylene foam, it resists moisture and weather for year-round durability.
- • **Precision Fit for Every Gap:** Snug 3/8 inch diameter seals medium cracks flawlessly, preventing drafts and dust intrusion.
- • **Cut-to-Perfection Versatility:** Trim or twist to customize length and thickness, adapting effortlessly to any joint or crack.
- • **Effortless Installation, Instant Impact:** Push into gaps with zero mess—no adhesives needed—then caulk over for a professional-grade seal.

## Overview

The M-D Building Products Versatile Gray Foam Backer Rod is a 20-foot, 3/8-inch diameter closed-cell polyethylene foam designed to fill and seal medium-sized gaps in concrete, expansion joints, and cracks. Weatherproof and easy to trim, it provides a durable, airtight base for caulking, enhancing insulation and draft prevention both indoors and outdoors. Trusted by professionals and DIYers alike, it ensures long-lasting protection and improved home comfort with hassle-free installation.

## Description

desertcart.com: M-D Building Products - Versatile Gray Foam Backer Rod - Essential Caulk Saver for Sealing Concrete Gaps, Expansion Joints, and Crack Filling, 3/8 by 20 Feet (71464) : Industrial & Scientific

Review: Works well for insulation also - Stuffs easily into door and window cracks to provide insulation in irregular sized gaps. And works well as intended caulk saver for large cracks.
Review: good product - worked perfectly

## Features

- Quality Construction: This gap filler is made from high-quality, weather-resistant materials, ensuring long-lasting durability and performance. It effectively seals medium gaps between surfaces, preventing drafts and dust from entering your home. Suitable for both indoor and outdoor use, it withstands various weather conditions, providing consistent protection and improved comfort.
- Concrete Gap Filling Excellence: Our product excels in filling concrete gaps, creating a strong foundation for caulking projects. Utilize this foam to effectively fill joints between surfaces, ensuring dependable adhesion for caulking applications that promise enduring durability and resilience.
- Complete Gap Solution: This product provides versatile gap filling, preventing drafts and offering a sturdy base for caulking. Perfect for expansion joints in driveways and sidewalks, it can be twisted for larger gaps and easily trimmed with scissors to the desired size.
- Effortless Installation: Enjoy a hassle-free setup by effortlessly pushing the backer rod into most joint openings until it fits snugly. Once installed, enhance the seal further by applying caulk on top—no need for messy sealants or adhesives.
- Versatile Application: From repairing leaky roofs and window sills to addressing drafty doors, the Backer Rod is your go-to solution! Beyond sealing surface gaps, it excels in insulating, enhancing airtightness, and damp-proofing your home—offering multifaceted benefits for various household needs.

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B000BQS90G |
| Batteries Included? | No |
| Batteries Required? | No |
| Best Sellers Rank | #8,467 in Tools & Home Improvement ( See Top 100 in Tools & Home Improvement ) #1 in Rope Caulk #32 in Industrial Sealants #1,731 in Hardware |
| Brand | M-D Building Products |
| Certification | Non-absorbent, Closed-cell Polyethylene Pre-caulking Material |
| Color | Gray |
| Customer Reviews | 4.6 4.6 out of 5 stars (1,619) |
| Date First Available | June 15, 2006 |
| Global Trade Identification Number | 00043374714647 |
| Included Components | MD Building - 71464 - 2pk |
| Is Discontinued By Manufacturer | No |
| Item Form | Foam |
| Item Package Quantity | 1 |
| Item Weight | 0.6 ounces |
| Item model number | 71464 |
| Manufacturer | M-D Building Products |
| Material | Rubber |
| Measurement System | US |
| Number Of Pieces | 1 |
| Number of Items | 1 |
| Part Number | 71464 |
| Pattern | Solid |
| Product Dimensions | 14 x 8 x 2 inches |
| Shape | Round |
| Size | 20 Ft. |
| Style | Backer Rod |
| Surface Recommendation | wall |
| UPC | 043374714647 |
| Unit Count | 1.0 Count |
| Warranty Description | All M-D products are warranted to be free from defects in material and workmanship if installed and used in strict accordance with our installation instructions. |
| Water Resistance Level | Waterproof |

## Product Details

- **Brand:** M-D Building Products
- **Color:** Gray
- **Item Form:** Foam
- **Item Weight:** 0.6 Ounces
- **Surface Recommendation:** wall

## Images

![M-D Building Products - Versatile Gray Foam Backer Rod - Essential Caulk Saver for Sealing Concrete Gaps, Expansion Joints, and Crack Filling, 3/8 by 20 Feet (71464) - Image 1](https://m.media-amazon.com/images/I/61bhNB8Z9UL.jpg)

## Available Options

This product comes in different **Size, Style** options.

## Questions & Answers

**Q: how many feet come in a 3 pk?**
A: Both INDIVIDUAL packs - the 3/8" and the 1/2"-  are 20 feet long.

**Q: no 1/4" one? either 20 or 50ft?**
A: Not in this brand, but Amazon offers 1/4-inch backer rod in various lengths, from 10 feet to 100 feet, from other brands. Just search on "Backer Rod 1/4 Inch".

**Q: can the backer rod be sliced for smaller openings?**
A: I have not done that, but it cuts easily with a sharp knife or scissors, so you should be able to slice it to fit whatever opening you have. It's good stuff!

**Q: Can his be used for exterior windows before caulking?**
A: I used it to push into larger cracks in my driveway before applying concrete filler, and it worked great. I'm thinking that it should work well for filling in spaces around your windows prior to caulking.

## Customer Reviews

### ⭐⭐⭐⭐⭐ Works well for insulation also
*by M***N on February 8, 2026*

Stuffs easily into door and window cracks to provide insulation in irregular sized gaps. And works well as intended caulk saver for large cracks.

### ⭐⭐⭐⭐⭐ good product
*by A***E on January 6, 2026*

worked perfectly

### ⭐⭐⭐⭐⭐ Exactly what I needed
*by B***I on January 9, 2026*

Worked perfectly for the gap between the stair siding and wall letting up cold air. No more draft! Sturdy material and comes in one long piece so you can cut to size. Decent price

## Frequently Bought Together

- M-D Building Products - Versatile Gray Foam Backer Rod - Essential Caulk Saver for Sealing Concrete Gaps, Expansion Joints, and Crack Filling, 3/8 by 20 Feet, (Pack of 2) (71464)
- M-D Building Products - Versatile Gray Foam Backer Rod Set 1/2in x 20ft - Essential Caulk Saver for Sealing Concrete Gaps, Expansion Joints, and Crack Filling (71480)
- Sikaflex Self Leveling Sealant, Gray, polyurethane with an accelerated curing capacity for sealing horizontal expansion joints in concrete, 10.1 fl. oz Cartridge

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*Product available on Desertcart New Zealand*
*Store origin: NZ*
*Last updated: 2026-03-06*