---
product_id: 4877844
title: "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)"
brand: "m-d building products"
price: "£6.28"
currency: GBP
in_stock: true
reviews_count: 13
category: "M D Building Products"
url: https://www.desertcart.co.uk/products/4877844-m-d-building-products-versatile-gray-foam-backer-rod-set
store_origin: GB
region: United Kingdom
---

# 0.5in max gap fill easy trim & install weather-resistant foam 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)

**Brand:** m-d building products
**Price:** £6.28
**Availability:** ✅ In Stock

## Summary

> 🛠️ Seal smarter, save bigger—your gap’s new best friend!

## Quick Answers

- **What is this?** 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) by m-d building products
- **How much does it cost?** £6.28 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.co.uk](https://www.desertcart.co.uk/products/4877844-m-d-building-products-versatile-gray-foam-backer-rod-set)

## 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

- • **Seal Like a Pro:** Effortlessly fills and seals medium concrete gaps up to 1/2 inch for airtight, draft-proof joints.
- • **Multi-Purpose Master:** Perfect for expansion joints, crack filling, and even creative DIY uses like ear post cores for dog owners.
- • **Save Caulk, Save Money:** Provides a sturdy base that reduces caulk usage, making your sealing projects more efficient and cost-effective.
- • **Cut to Fit, Push to Seal:** Customizable length with easy trimming and simple push-in installation—no adhesives needed.
- • **Built to Brave the Elements:** Crafted from durable, weather-resistant foam that stands strong indoors and outdoors, rain or shine.

## Overview

The M-D Building Products Versatile Gray Foam Backer Rod is a 1/2 inch by 20-foot weather-resistant foam designed to fill and seal medium gaps in concrete, expansion joints, and cracks. Its durable construction ensures long-lasting performance indoors and outdoors, while its easy-to-trim and push-in design simplifies installation. Ideal for professional-grade caulking projects, it also offers unique versatility for creative DIY applications, making it a must-have for efficient, cost-saving home improvement.

## Description

Product description Compare Backer Rod Small Gray Backer Rod Medium Gray Backer Rod Large Gray Backer Rod Ex-Large Gray Backer Rod XX-Large Gray Backer Rod

Review: Great quality & sealing ability, highly versatile & easy to use. - High quality & works just as advertised. Seals like a champ. When it comes to sealing air gaps whether it be around window frames, doors, moldings, baseboards, concrete, etc. you get what you pay for. Go for the better quality. It's easy to use, cut, install, highly versatile. This is a great & trusted product.
Review: This does the job. Strong and durable! - So we had a bathroom done and the guy messed up the job. This stuff was a great easy fix for the gap between the wall and sink cabinet and its strong. We were able to calk after filling the gap. Now you can't even tell. I didn't even know there was such a thing. Reasonably priced and a great filler for gaps when remodeling.

## 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 | B000BQWOC0 |
| Best Sellers Rank | #2,119 in Tools & Home Improvement ( See Top 100 in Tools & Home Improvement ) #22 in Weather Stripping |
| Brand | M-D Building Products |
| Brand Name | M-D Building Products |
| Color | Gray |
| Customer Reviews | 4.6 out of 5 stars 3,897 Reviews |
| Global Trade Identification Number | 00043374714807 |
| Included Components | 1 Foam Backer Rod Roll |
| Item Form | Specialty |
| Item Type Name | Backer Rod |
| Item Weight | 0.02 Pounds |
| Manufacturer | M-D Building Products |
| Material Type | Foam |
| Maximum Gap Fill | 0.5 Inches |
| Model | 71480 |
| Number of Items | 1 |
| Part Number | 71480 |
| Surface Recommendation | wall |
| UPC | 043374714807 |
| Unit Count | 1.0 Count |
| Water Resistance Level | Waterproof |

## Product Details

- **Brand:** M-D Building Products
- **Color:** Gray
- **Item Form:** Specialty
- **Item Weight:** 0.02 Pounds
- **Maximum Gap Fill:** 0.5 Inches

## Images

![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) - Image 1](https://m.media-amazon.com/images/I/61UnawlcwQL.jpg)
![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) - Image 2](https://m.media-amazon.com/images/I/81JSrbnZQ5L.jpg)
![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) - Image 3](https://m.media-amazon.com/images/I/818J6gOM3ZL.jpg)
![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) - Image 4](https://m.media-amazon.com/images/I/81Py1S2524L.jpg)
![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) - Image 5](https://m.media-amazon.com/images/I/81-xBTntOuL.jpg)

## Available Options

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

## Questions & Answers

**Q: Is it safe to use near hot water baseboard radiators? I want to use it behind radiator cover as a temporary fix for a cold draft.**
A: I suspect it would be safe if between the wall and the top cover of the baseboard, assuming you have standard baseboard covers like mine -- which never get super hot. It's foam, and will likely melt if too close to a heat source. To be on the safe side, I'd suggest first contacting the company directly.

**Q: Can you use barge glue and plastidip**
A: Call the manufacturer

**Q: I live in an apartment and i feel a draft coming through the cracks of my window would this help? Im trying to avoid using weather tape**
A: I purchased the medium backer rod and they are 1/2" thick. I think the one I purchased would be too thick to insert into the crack of your windows.  Maybe there is a smaller version that would work for you.

**Q: What caulking do u need for this ?**
A: I did use caulk as it was used to support a garage door seal as the bottom of the door.

## Customer Reviews

### ⭐⭐⭐⭐⭐ Great quality & sealing ability, highly versatile & easy to use.
*by J***N on March 31, 2026*

High quality & works just as advertised. Seals like a champ. When it comes to sealing air gaps whether it be around window frames, doors, moldings, baseboards, concrete, etc. you get what you pay for. Go for the better quality. It's easy to use, cut, install, highly versatile. This is a great & trusted product.

### ⭐⭐⭐⭐⭐ This does the job. Strong and durable!
*by G***S on April 18, 2026*

So we had a bathroom done and the guy messed up the job. This stuff was a great easy fix for the gap between the wall and sink cabinet and its strong. We were able to calk after filling the gap. Now you can't even tell. I didn't even know there was such a thing. Reasonably priced and a great filler for gaps when remodeling.

### ⭐⭐⭐⭐⭐ Soft, Flexible Support That Worked Well for Ear Posting
*by M***S on May 3, 2026*

This foam backer rod turned out to be a useful material for my puppy’s ear posting needs after surgery. It’s lightweight, soft, and flexible, which made it comfortable enough for short-term use while still providing enough structure for support. It was easy to cut and shape to the needed size, and it didn’t feel overly rigid or harsh against the skin when used carefully with proper wrapping. That balance of cushioning and structure made it practical for keeping things stable during the healing process. Overall, it’s a simple, adaptable material that works well for gentle support applications like ear posting when used thoughtfully and with care.

## Frequently Bought Together

- 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)
- 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)
- 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 United Kingdom*
*Store origin: GB*
*Last updated: 2026-05-23*