How to Unwarp Wood

How to Unwarp Wood: Easy and Effective Method Discussed

I enjoy buying fancy wooden furniture for my home. The natural beauty of wood gets me like anything.

Now imagine seeing your beautiful wooden furniture getting warped over time. In this post, I will explain how to unwarp wood.

Just like you, I had this question in my mind, what made wood to warp and how it can be prevented.

Wood is a natural material that warp when exposed to heat and moisture. No one likes their wood to be twisted and in an odd shape.

The best way to fix this problem is by applying extra heat and moisture to the opposite side of the warp.

However, this unwarping method works only on minor warping cases. For more severe cases, you will have to take more serious steps.

Now that you have reached here, l will tell you the right method to unwarp wood and everything else you should know about wood warping.

How To Check For Wood Warping?

How To Check For Wood Warping

If you are wondering, how to check for wood warping, no worries, I got you covered. I have a very simple method to check wood warping.

Here’s what you have to do:

  • Take a piece of wood and place it on a flat surface.
  • Now check along the edges of the wooden piece.
  • If you notice any end or part of the wooden board is raised, then it is warped.

You need to check all the faces of the board, following the same trick. This is the best way to confirm the uniformity of a wooden board. Now that we have discussed the way to check for wood warping, let’s check out how to straighten warped wood.

Why Does Wood Warp?

There is not just one but many reasons that cause wood to deform. Before I tell you how to fix it, you should at least learn the reasons of wood warping. That being said, let’s dive into the details now.

1. Bad Weather Conditions

One of the main causes of wood warping is bad weather conditions. The sudden rise or drop in temperature can have a major impact on natural wood.

In cold weather, wood tends to shrink in size, whereas, in summers, they get swollen. This sudden change in temperature is what causes industrial wood products to crack or warp.

2. Poor Quality Of Wood

Poor Quality Of Wood

If you are less careful while installing low-quality wood or wooden products in your house, it is inevitable for your wood products to suffer warping or damage.

Woods that are not high in quality are more easily warped. That’s because the connection of fiber in low-quality wood is loose and therefore, they can be easy. This is why I would advise you to opt for higher quality wood products so that you can prevent it from happening.

3. Unsuitable Use And Care Of Wood

If you don’t take enough care of your wooden furniture during use, it is inevitable for it to get damaged. If you expose your wood products often to sun rays and water, it will lead to wood warping.

Wood warping can also happen when you store wood in a humid space for a long time. The excess moisture absorbed by the wood will make it deformed. The moisture content of wood products is only 8 to 10%.

Related: way to fix swollen wood furniture if they are damaged by water?

4. Destruction From Insects

Another very big problem that can lead to wood warping is insects. Ants and carpenter-bees live in fiber which leads to loose fiber connection in the wood.

When you let the insects stay in your wood products for long, it eventually damages the wood. Therefore, you should get rid of them at once.

5. Problems During The Arrangement And Processing

Many of you may not know this but some industrial woods are more deformation-prone. Even slight movements can cause such wood to warp.

If the edges of the wood product deviate from its actual shape, there is no way you can stop it from warping.

Different Types Of Wood Warp That You Will Face?

Different Types Of Wood Warp That You Will Face

Wood warping can be of different types, depending on the cause. To be able to fix them, it is important for you to first understand the ways wood warp.

Here you go with the details:

1. Crook

In this type of warping, there is movement along one edge of the wood.

2. Cup

This is the type of warp where the wood deviates from a straight line across the width of the wood.

3. Bow

In this form of warping, the wood deviates from its initial flatness, lengthwise.

4. Kink

This is warp form where the wood deviates from the edge from a straight line, from end to end.

5. Twist/Wind

In this type of warp, the four corners of the face of the wood are no longer in the same plane.

How To Fix Warped Wood In Different Ways?

There are many different ways to fix a warped wood. To help you out, I have listed some of the most common ways that are used by the woodworkers. The methods listed below are the most effective ways of unwarping wood.

1. Heat

Heat is one of the most common methods used to unwarp wood. There can be different types of wood deformation including twisted, cup, bow, etc. It is always not possible to unwarp the wood into its original shape. But you can get close to fix the problem, only when you know how to use heat properly.

Heat is considered to be one of the most effective remedies for wood unwarping. Here are the steps you need to follow to unbow wood warping:

  • At first, you need to clamp the whole board on a flat surface. A flat table or floor would be great.
  • Now apply the heat to the board. You need to put more pressure on the affected areas. You need to continue applying heat until it gets very hot.
  • After that slowly bend the warped board and wait for it to cool down. By doing this, you can turn the deformed wood in its original shape.

But keep in mind not to overheat the wood as it can damage the wood.

2. Using an iron

The next method you can try is using an iron. I have explained the entire method in detail below. Check out the steps and you will know what to do.

  • At first you need to wrap the board in moistened towels. Take two large towels or rags and moisten them. Wrap them around the board nicely. Make sure that the affected area is covered.
  • The towels you are using should be big enough to cover the entire board, as in no part should be left uncovered. You need to choose towels that can take the heat of an iron.
  • When moistening the rags or towels make sure that you wring out the excess water. They should not be dripping wet.
  • Now place the towel-covered board on an ironing board or any other flat surface. Keep in mind, to place the concave surface face down. Also, make sure that the surface you are using is strong enough to withstand the high heat.
  • Next, you need to heat the iron to the highest point. The best thing would be to use a steam iron as they are more effective.
  • Once the iron is all hot, press it on the warped surface and slide it over the entire surface. You need to apply even pressure all over the board.

To get the best results, hold the iron for 5 to 10 seconds and then shift it to the next spot. Make sure that you cover the entire board and not just the warped areas.

  • You need to repeat this as many times as it is needed. You can stop, once the problem is fixed.
  • After you have unwarped the board, remove the cover and allow the board to dry thoroughly.

This process may not be effective on all warped boards. If you don’t see any progress even after repeating the steps multiple times, then you should try some other method.

3. Using sunlight

Using Sunlight

Sunlight is also a good source of heat and therefore, you can use it to unwarp wood. Here are the steps to be followed:

  • Take several towels and moisten them. Wrap them around the warped wood. You can also take rags or sheets. No matter what you take it should be big enough to cover the wood completely.

Before wrapping the towels, wring the excess water. The towels should be moist and not drenched.

  • Now place the covered wood under direct sunlight. Find an area that receives a lot of sunlight during the day. You need to place the wood with the concave side face down.

You can get the best results from this method during dry, warm weather. To make the method more effective, you need to place the wood on a rigid and flat surface.

  • You may have to keep the wood in sunlight for at least two to four days. During this period, you need to spray the covered wood with additional water to keep it moist.

The direct rays from the sunlight will heat the wood and help it to absorb moisture from the towels. This will help the warped wood to regain its original shape again.

  • You need to dry the wood until the problem is fixed. This can take several days, so you need to hold your patience before you see any progress.
  • You should keep a check on the wood daily. Once the wood is unwarped, you can remove the towel and allow it to dry.
  • At night, bring the wood inside and keep it in a dry and warm place
  • In case, you don’t see any progress after two to three days, then you are either doing it wrong or have to try some other method.

4. Using Pressure

The next best method is the use of pressure. This method is considered to be more effective than all the previous methods we discussed. Here is what you have to do:

  • Take some damp paper towels and place them over the concave side of the wood. You can also use a steaming towel or paper if you don’t have paper towels.

The material you use should be moist and cover the entire wood. Before you start make sure that you have drained all the excess water from the paper towels.

  • You need to apply the moist paper towels on the concave surface of the wood. By applying moisture on the warped area, you can unwrap the wood. All the moisture will be absorbed by the concave side, while the convex side will dry out.
  • Wrap multiple layers of plastic over the paper towels and make sure that they are tightly wrapped around the wood. This will slow down evaporation and thus, keep the wood moist for long hours.
  • Now place the wood in a clamp and tighten it to unwarp the affected area. You need to be careful while performing this step. Applying too much pressure can damage the wood.

You need to leave the wood clamped for at least 7 days. Keep a check on the wood regularly. In case, you notice your wood getting damaged, then remove the clamp immediately.

  • The place where you clamp your wood should be warm. The best temperature is 65 degrees Celsius. You can either use a heat lamp or keep it under direct sunlight. You can also place it under an electric blanket. A warming mat will also work well. You need to apply heat on the wood for six to eight hours every day.
  • After 7 days, remove the clamp and unwrap the wood. You need to let the wood dry thoroughly.
  • Check whether the warp has vanished or not. If yes, then you are ready to use the wood. If no, then you need to apply more pressure. This time let the wood in a clamped position for two to three weeks.

Make sure that the temperature is around 25 degrees Celsius. The place where you store it should have no moisture in the air.

  • Keep a check on the progress regularly. Once the wood dries completely, you can remove the clamp.

If this method has not worked for you, then you should know that the damage caused is impossible to reverse.

5. Using Winding Sticks

Now we are going to use winding sticks to straighten the wood. This is one of the easiest methods to straighten wood.

Here you go with the steps:

  • The first thing you need to do is to determine the type of warp. For this, you need to place the board on a flat surface and use winding sticks.

With the help of winding sticks, you can identify bow or twists. Along the board’s length, look for level sticks. If an ‘X’ shape is formed, it means there is some curving on the surface. To correct this, place the board diagonally along the high line.

  • To find out whether your board is bowed, you need to use a single winding stick.

Drag the winding stick along the surface of the board. If you spot a gap between the board and the stick, then it’s bowed. If the board is low in the central part, make cuts that will remove the high sections on all the edges.

  • In case, the board piece is higher in the middle section, make cuts particularly on this part to create a lower piece in the middle part. You need to repeat the above steps to make sure that the board is straightened.

6. Fix 2 Ends of Wood Plates

Fix 2 Ends of Wood Plates

This method is best suited for unwarping small wooden plates. All you have to do is just get some nails, a hammer and pliers. This method is not only time saving but also very easy.

You just have to use the nails to fix both the ends of the warped wooden plate. After that, you will have to remove the nails using the pliers to complete the process. With the help of this method, you can immediately unwrap the small wooden pieces.

Also read: difference between wood glue and liquid nails.

7. A Collaboration Of Moist Cloth, Nylon Paper, And Pressure

The last method is to use a moist cloth with nylon paper and pressure. Uneven moisture can cause the wood to bend, warp or twist. Therefore, it serves as a favourable situation to turn your wood back to its original shape. This will help you to get the best results.

Here are the steps to be followed:

  • First, get a damp cloth ready. Use the cloth to cover the warped wood.
  • After that take a nylon paper and wrap the covered wood nicely. Make sure no place is left uncovered. This will help retain the moisture inside.
  • In this step, you need to prepare heavy stuff such as stone or brick. You will need this to apply pressure on the warped wood.
  • You need to place it on the warped areas of the wood and let it stay like that for at least two to three days. If needed, you will have to let it stay like that for long.

This is yet another effective way to straighten warped wood. To get the best results, follow all the steps closely.

Ways to Prevent Wood From Warping

As they say, prevention is better than cure. If you can prevent wood warping, then you don’t have to take the pain to fix it. There are few effective ways following which you can prevent wood warping.

1. Inspection

The best thing to do is to inspect the wood at the time of purchase. This method is applicable, only when you are choosing the pieces of lumber you are buying. In that case, you can inspect all the pieces of lumber.

There is a special type of device that can be used to check the moisture content of the lumber.

2. Woodgrain

This is one of the most difficult ways to prevent wood warping. There are three different ways of cutting lumber. This include, quarter-sawn, flat-sawn, and rift-sawn.

This method involves controlling the board from where it is cut from the log. With the flat-sawn technique, the board is cut flat, while ignoring the grain. Quarter-sawn is the compromise between the two. It gets closer to the orientation of the grain. This is more stable than the flat-sawn technique and also much less wasteful.

3. Storage

Storage

The next best option is to store your lumber with adequate ventilation. You need to make sure that your lumber is sitting flush.

There should be no deviations between the lumber sizes. This means you will have to make separate stacks for different board dimensions.

You can also read what type of wood is used in the construction?

4. Proper Curing and Drying

You can also follow proper drying and curing wood to prevent warping. Here is what is recommended by experts:

  • You should not allow the semi-dry board to retain moisture.
  • You should not dry your board too slowly.
  • You should not over dry board as it can lead to splits and cracks.

You can also seal the ends of lumber to prevent warping that is caused by uneven drying.

Safety Issues That You Should Take Care While Unwarping Wood

No matter what method you are using to straighten your wood piece, you need to maintain safety precautions. Working with heat and heavy items to create pressure can be dangerous at times. Therefore, it’s better to be prepared than to be regret later.

Before you start the unwarping process make sure that you are wearing all your safety gear.

  • You should wear protective gloves that are heat resistant so that you don’t burn your hands or finger while using an iron.
  • When using the pressure method, make sure that you do it in a safe place. In other words, you should place the wood on a hard and strong surface, so that it doesn’t break.

Final Thoughts:

Wood warping is a natural process and it is tough to prevent it. The times when you cannot prevent it, you should know the right steps to fix it. The methods listed above are all very effective.

If one method is not working for you, then you can try the other one. While performing any of the methods, make sure that you maintain full safety. Hopefully, now you know how to unwarp wood. You can follow the steps mentioned in the article when the time comes.

For other wood related discussions, please follow Ronaldphillipsantiques.

57 thoughts on “How to Unwarp Wood: Easy and Effective Method Discussed”

  1. The piece of wood that I have which is warped is a door of a cupboard. The entire piece of furniture is highly hand-carved. The piece of furniture has been in my family for over a hundred years. The furniture was hand-made in (Ceylon) Sri Lanka I believe.
    I am not sure which method I can follow given the from is very heavily carved

    1. As it is very old piece of furniture. Please start with minimum heat or you can also use iron to observe the improvement.
      I personally do not suggest to apply pressure.

  2. I have an antique table with leaves that fold down that needs to be refinished. It was left on a covered porch. Moisture has caused the leaves that fold down to bow. After reading your suggestions I was thinking about turning the table upside down, placing wet towels, heat and some pressure. What are your thoughts?

  3. What I read hear seems to be for board warp but I have a couple of raised panel doors that are unfinished and no longer lay flat. I’m looking to get them flat again so I can finish them and use them on a cabinet I have. Any suggestions?

  4. I have a fairly large board 5’x 2 1/2’ with decorative carvings on one side (about 8 inches top to bottom on front). It is the board that covers the tuning block and hammers on a 100+ year old piano. I’m assuming the warping was from being in direct sunlight. Should I remove the finish before trying any of these methods and which would you recommend? Thank you

  5. Unbelievable!!!! It worked so beautifully in 2 days for 2 severely warped pressed wood shelves!
    I live in Az so hot sun was perfect! I laid them flat and put soaked towels on changing twice a day as they dried out. I put larger flower pots in center of each. Today I have them sitting in sun to make sure dry. Thank you so much as they are large garage shelves and would have been expensive to replace. Really appreciate all your advice!!!! Bobbi

  6. I have a maple board that is 1 5/16” thick, 24” x 28” and glued across the 24” side. (Four 28” boards glued together to create a 24” width) The boards are bowed across the the width. Does the fact that they are glued present any problems for fixing? Which method would you recommend?

  7. Hi – I am rebuilding a couch from the 40″s. The wood pieces across the bottom have warped – if I can unwarp them, do you think they will still hold the bottom of the couch together. The wood seems very hard and strong still – no rot. thanks.

  8. Hi, I have cut wooden discs that I left in the garage over winter and have started to work on them. Bringing them inside with central heating appears to have warped them so they create a concave kind of bowl. I’m not sure what technique to use for this problem.

    Thanks!

    1. You have to be very careful to avoid cracking the wood in any of the process.

      I suggest our 4th method: Using Pressure

      But be very gentle and slow. Please do not speed up the process.

  9. Help! I have a 78” beautiful round dining table. It is only a little over a year old. Unfortunately the company that made the table did not make it through COVID and closed its doors. It is bowing pretty badly on one side. What can I do? We paid a lot of money for this custom table due to size. Really hoping you can help with a solution. Thank you!

    1. For the raw woods pieces, it is easy to work. But working on complete furniture is pretty hard. 🙁

      This fixing needs to be done via expert cuz wood is really sensitive.

      To fix this, you have to be very very careful. If I could get a picture then it would be easy for me to explain.

      Iron method works good but in this process wood might get discolored. You need to fix that too.

  10. I have 54″ hickory mop handles that are bowed to varying degrees. What method do you suggest for straightening those?

  11. How would you go about flatterning a macrocarpa table top that has had resin poured on top?

    We thought we could flattern out the bow with resin but after the pour we realized that double the amount was nessacery and we didn’t want to spend more on resin.

    Thought it might be difficult to reverse the bow, as heating the table top will melt the resin. What do you think is the best method to fix this issue, cheers

  12. Hi there. Please help! I have acquired a sheesham coffee table with chest component on one side and drawers on the other. It has warped quite badly where the sides meet the feet causing lateral distortion of the piece and the breaking of the corner joins. I was thinking of trying to screw the gap closed after applying moisture? I can send pictures if it’s easier. Thank you!!

  13. We have a 100 year old house with solid wood panel doors. One door can’t close all the way because the middle of the door bows slightly towards the jamb/closing side and rubs on the trim. What would be the best way to reduce this without stripping/sanding and repainting the entire door? Maybe pressure then add a third hinge to keep door straighter?

  14. Darlene Bowman

    I am in the process of refinishing an antique dresser. I sanded and stained the drawers (I haven’t sealed them yet). When I put the drawers back in the dresser I noticed that the middle one is quite badly bowed inwards. Can I use one of the above mentioned methods to try to fix this drawer? Thank you.

  15. I have a round ceramic tile patio table that is horribly sagging in the center. The top tiles are small are not damaged at all but the wood the tiles are attached to has a bowed. I tried just turning in over for months but still bowed. Maybe I should try pressure like stone blocks? But am hesitant about the tiles breaking loose. Thoughts please?

    1. Yes, you are correct. Pressure method has risks in this situation.

      If possible, then please try using an iron. But please be very careful.

  16. I have a 2″ (5cm) thick walnut slab with a bulge around a knot on one side. Are the techniques you mention above going to be effective on such a thick board?

  17. I have a 2.4m (70mm wide/20mmthick) length of redwood on a garden swing seat which has warped. It is treated with Cuprinol water based garden furniture paint. Will the iron/towel method work without removing the paint?

  18. I have a Jasper Co slant front secretary with bubble glass doors. The drop down desk top is bowed causing the veneer to separate. What method if any should I try?

  19. Hannah J Parrish

    My guitar fretboard are warped due to excessive string tension. I even see a few small cracks. What suggestions do you have for fixing the warping? Thank you so much

  20. I have a 2′ x 3′ x 3/4″ panel of edge glued pine. During the many steps required to seal it (using Minwax Polycrylic), it has started to bow. Since I want to paint on it with acrylic and then hang the painting, unframed, how can I a) straighten the panel, and b) keep it straight afterward? Thank you!

  21. Wide drawer for utensils under cooktop has warped possibly due to heat element. We tried pressure inside drawer on the floor without wet paper towels. Would it be better to turn drawer over, insert wet paper towels and add pressure to unwarp drawer? Thank you for your reply.

  22. I built a bar in my log cabin, and tiled the top, in the winter it’s straight but in the summer it bows up, again in the winter it goes flat again, is there anything I can use to soak in the wood in the winter so it doesn’t bow again in the summer

    1. Hi Donna,

      Sorry but there is nothing you can soak in the wood to prevent this. You can use some of the methods in this post to fix it but if it continues to receive heat and sun it will happen again.

  23. I’ve got some rough cut spalted willow slabs that are roughly 6’x16″x1½” that are cupped in the center down the length of each slab. The worst one is about ¼” cupped. I’ve ironed them some & it’s helped a little but I’m not sure if I did it long enough. What do u suggest is the best way to get these flat & ready to be used for a desktop. Thank u

  24. I have a 120′ fence with 6′ 6×6’s as supports between 2 driveways. The fence has been up about 3 months. One of the posts bin the middle has bowed out of alignment at the top.
    The fence gets full sunlight here in central Illinois. Any suggestions?

  25. Hello Ronald,

    I can flatten a cupped board (3 feet long, 10″ wide) but it soon becomes cupped again.
    If I flatten the board, then cut 2″ lengthwise strips from it as planned, will each strip later cup across its 2″ width?

    Thanks

  26. Thanks Ronald, Since the 6×6 is in 2 ft of concrete, I think I’ll get a couple of wet towels and sandwich them between a 4′-5′ board on the concave side and then draw in with a clamp in slow increments. Does that sound reasonable?

  27. We have a antique table with inlay wood for the top. We want to keep it outside under the overhang as it’s a great space for it. The inlays are starting to warp despite me oiling it. Should I get a professional to put a tile or concrete top on it?

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