Nothing will stop a massive flood but if your house is prone to flooding from heavy rains there are some simple steps you can take to prevent it.
Here are 15 ways you can stop your house from flooding when it rains:
- Check and clean your drains.
- Upgrade and rearrange downspouts.
- Waterproof window wells.
- Seal basement windows.
- Stuff the air bricks.
- Plug sinks and baths; block toilets as well.
- Find (and fix) water entry points.
- Leave some space between your mulch and siding.
- Place sandbags around your home.
- Make a slope.
- Fill the low spots in your foundation.
- Install foundation vents and a sump pump.
- Install a cavity drain system.
- Place back-flow valves in your sewer.
- Raise your home on stilts and piers.
Let’s get right into it.
1. Check and Clean Your Drains
Prevention is better than cure, especially when it comes to flooding.
If you want to stop your house from flooding, you should first check your drain. It should be free from leaves and other debris.
Should there be any debris, sweep up and empty them in your yard waste container. Don’t leave them ungathered in the yard, for they may wash to the city drains and clog them.
2. Upgrade and Rearrange Downspouts
If heavy rains are about to pour soon, you can prepare ahead by upgrading and rearranging your downspouts. These are pipes that carry the rainwater that accumulates in the gutter.
You can avoid flooding by arranging downspouts in such a way that the water is carried 6-10 feet (1.83-3.05 m) away from your home’s foundation.
For best results, provide a 1/16-inch (0.16 cm) slope for every 10 feet (3.05 m) of gutter length.
If your gutters tend to overflow, it would be wise to use larger gutters or add more downspouts around your property.
3. Waterproof Window Wells
While window wells work to prevent moisture from damaging windows at/below grade, they put your house at risk of flooding.
You can avoid this from happening by installing a drain pipe filled with gravel around your window well. Remember to link the window wells’ drainage to the foundation drains.
If creating a drain isn’t possible, install window covers that can be bolted in place. That way, you can keep these openings watertight.
4. Seal Basement Windows
Another way to prevent floodwater from entering basement windows is to seal them.
First, you need to check the windows for drafts.
If air is coming in, then water will come in too.
One hack is to place the lit candle close to the window seams. If the flame bends, then it’s a sign that air is seeping through that seam.
You can re-caulk these drafty areas as necessary. However, it’s best to remove the existing caulk on the window — in case there are.
To do so, you need to:
- Apply caulk softener to the areas. Leave it on for two hours.
- Once this time has elapsed, use your putty knife to remove the old caulk. Make sure to get rid of everything.
- Clean the surface with a wet rag. The new caulk won’t stick if the area contains debris.
Once the site is spotless, you can apply the caulk inside and outside of the windows.
For reference, you’ll need one tube of caulk for every window.
Remember to smooth the caulk with your wet fingers. More importantly, let the caulk dry for 15 hours or more.
5. Stuff the Air Bricks
If you have air bricks instead of basement windows, it’s another entry point for heavy rains.
To prevent floodwater from entering your home, stuff these air bricks with towels, cloths, or plastic covers.
You can also purchase an air brick cover, which you can easily install to cover the opening.
6. Plug Sinks and Baths; Block Toilets As Well
Flood water can back up to your sinks, baths, and toilets. Unless your sewer has a back-flow valve (which will be discussed below), it’s best to plug or block them.
Of course, the easiest way is to place a plug on your sink or bath.
Likewise, you can use any of the following to cover the drain. Make sure to place a sandbag or any heavy material on top of them, though (source).
- Empty coffee pod or medicine cup. Plug the drain with an empty coffee pod or a 15 ml (0.51 oz) medicine cup. Should they be too small for your drain, wrap them around with rubber bands until it makes a seal.
- Jar or plastic lid. Position the lid so that it lies flatly on the drain. You can make a more robust seal by wetting the cover and pressing it hard on the surface.
- Plastic bag. Insert a washcloth or sponge in a plastic bag and roll it so that it fits the drain. Squeeze as much air out from the plastic as you can. Stuff it into the drain until it makes a good seal. As for your toilet, you can weigh down lids easily with towels or bed sheets.
7. Find (and Fix) Water Entry Locations
Use your hose to spray water on your home’s exterior foundation. It should help you find cracks that may bring flood water into your house.
To fix these leaks, you need to:
- Clean the area and remove old chips. If the crack is more than ⅛ inch (0.32 cm) wide, use a sledgehammer and cold chisel to get rid of the chips.
- Mix the concrete patch until it becomes a thin paste. It’s best to combine the powder with latex instead of water. The former should make the mixture more adhesive and elastic.
- Spray some water onto the crack. It’ll make for a more solid bond.
- Apply the patching paste or latex caulk. Use a trowel to scrape off the excess.
- Spray the patch with some water twice a day. It’ll help cure the patch and prevent cracks.
8. Leave Some Space Between Your Mulch and Siding
If you want to avoid sealing cracks over and over again, then remember to leave some space between your mulch and siding.
Wet mulch can rot the sides, leading to cracks that flood water can seep into whenever it’s raining.
Generally, experts recommend leaving a 12-inch (30.48 cm) gap between the mulch and your house’s siding.
If it’s flammable — meaning your mulch is made from wood or bark — then a bigger gap of three to five feet (0.91 to 1.52 m) is recommended.
Not only will this placement prevent mulch moisture from degrading your foundation, but it’ll also stop termites from invading your property.
9. Place Sandbags Around Your Home
Sandbags, which are frequently used to construct dikes and levees, offer good flood protection as well.
There are different sandbags, with burlaps working the best against low floods (depth of two feet or 0.61 m or below.) You can easily buy them at your nearby hardware store as well.
When it comes to flood sandbags, do keep these tips in mind:
- Choose the correct measurement. Your burlaps should measure 14 to 18 inches (35.56 to 45.72 cm) wide and 30 to 36 inches (76.2 to 91.44 cm) deep.
- Fill the burlap with heavy-bodied or sandy soil. Keep it to ⅓ to half its capacity (approximately 30 pounds or 13.61 kg). Double bag it as necessary.
- Don’t fill the burlap completely. It’ll get too heavy and wouldn’t make an effective water seal.
- Avoid coarse sand. They can fall out of the bag quickly.
- Don’t use gravel or rocky soil. They’re permeable — meaning they’re not as good as keeping water away.
- Observe the proper stacking process. The maximum number of sandbags you could stack on each other is three.
- The number of sandbags you need will depend on the size of your property. For starters, you have to use about 600 sandbags to cover a 100-feet (30.48-meter), one-foot-high section (0.3-meter).
- Protect your burlap sandbags when not in use. Make sure to cover them while in storage.
10. Make a Slope
Creating a 5-10% slope away from your property is another way to prevent flooding. It’s a gravity assist, if you may.
For reference, that’s about one inch (2.54 cm) per foot for about 10 feet (3.05 m).
Not only will this prevent foundation leakage, but it can help drain floodwater quickly as well (source).
11. Fill the Low Spots in Your Foundation
Ideally, the soil around your property should drop 2-3 inches or 5.08-7.62 cm (for every 10 feet or 3.05 m) from the foundation.
If not, you’ll have low spots that are more prone to flooding. These are areas where puddles and spongy soil develop after continuous rain.
To prevent this from happening, remember to fill the areas with compacted soil.
Here’s how to do so:
- Scrape the topsoil. Save them for later.
- Place a stake near the foundation. Tie it with the string.
- Extend the string for 50 feet (15.24 m). Affix it to the stake on the low spot.
- Attach the string level. Measure the distance from the ground to the string. It should be about 10-15 inches (25.4-38.1 cm).
- Replace with two inches (5.08 cm) of topsoil. Sow grass as needed.
12. Install Foundation Vents and a Sump Pump
Foundation vents are known as wet flood-proofing devices. In other words, they let water into your home instead of letting it pool around.
While it seems counterintuitive, it does work. It helps relieve the pressure that floodwater may put onto your basement windows or walls.
That said, foundation vents work best if you have a sump pump in your home as well.
It’s a device that helps remove floodwater from the sump pit, which is the lowest point in your system.
If you already have a sump pump at home, make sure to examine and clean it regularly.
Check to see if it’s working by pouring some water into the pit. Examine the discharge hose to see if it carries the water away from your property.
If you want your sump pump to drain faster, keep the pipes on sloped ground for gravity assistance.
13. Install a Cavity Drain System
A cavity drain system is a type C waterproofing device. It provides drained protection, thus keeping your home safe from floods and whatnot.
What’s great about this system is that you don’t need to make significant changes. After all, the process only involves covering the walls and floors with a cavity membrane.
A cavity drain system helps maintain an air gap, which should help your basement ‘breathe’ after some rigorous flooding.
Once the drainage system is in place, it’ll help channel the water out of your basement.
Unfortunately, installing this system is not a do-it-yourself task. You may end up with weak spots that will eventually lead to flooding.
For best results, get your cavity drain system installed by a licensed contractor.
14. Place Back-Flow Valves in Your Sewer
Even if you’ve followed all the tips above (and below,) your home may still flood if your sewer backs up.
That said, it’s best to install back-flow or check valves beforehand. As the name suggests, they can help stop water from ‘retreating’ back to your home.
Ideally, it should be installed before any fixtures should be placed.
While you can do this on your own, it’s best to leave it to the hands of plumbers or contractors. They’ll do it correctly while making sure that no building codes are violated.
15. Raise Your Home on Stilts or Piers
So this sounds extreme, but just hear me out here. If making a slope isn’t possible, your next best option is to raise your home on stilts or piers.
Do note that this is a slow process, so you need to have a head start.
Raising your home involves using a hydraulic jacking system that will crank your home up inch by inch.
It’ll then be pulled on stilts, which allows the construction crew to create a taller foundation.
Protecting your home from flooding often involves pre-emptive measures. Installing wells and sealing windows/cracks come in handy. Likewise, ensuring that your drains and downspouts are working is essential to keeping your home dry.
As a homeowner, I am constantly experimenting with making the structure of my house more energy-efficient, eliminating pests, and taking on DIY home improvement projects. Over the past two decades, my family has rehabbed houses and contracted new home builds and I’ve learned a lot along the way. I share my hard-learned lessons so that you can save time and money by not repeating my mistakes.