Tongue and groove separated on the edges

Q: I had engineered oak floors installed in October. They are tongue and groove, and were laid as a floating floor in my condo. Now, some of the boards have separated on the edges. The separation is around 3mm or so. What could be the cause? Thank you for your time.

A: I wouldn’t have expected this with an engineered floor. They are constructed similarly to plywood so the boards are very stable. I can’t imagine that the top, hardwood layer would be able to shrink independent of the other layers. And I assume this is a click type of joint. Generally this type of joint required inserting the next board on an angle and then pushing down to click them together. It shouldn’t just pull apart. Changes in moisture content are generally the cause of wood shrinking or expanding. I think I would contact both the installer and the manufacturer. If this was a solid hardwood floor, nailed down these gaps would be very minor and normal. I’m not so sure I can say the same for an engineered floor.

Follow-up Q: Thanks for your answer.

This is actually a tongue and groove system, and the boards are glued to each other on the edges. This is not click. This floor was installed as a floating floor. Does this change your opinion? I don’t know if this was an effect of moisture, but the moisture is not affecting any other area. Maybe the glue gave up?

A: Okay, interesting. I said ‘click’ because in the early days of laminate flooring, before click joints each panel was glued together, squirting the manufacturers recommended adhesive into the groove. Then they invented the various joints that snap together and the glue joint went away. But those floors, as laminates still are, are rather thin. Some engineered floors are not thin but rather 1/2″ to 5/8″ thick. I would be doing some research before relying on a glue joint install with a floor that thick. Here is what I would do. Go to the web site of the manufacturer, unless you have the directions that generally come with each box of flooring. Find out if they recommend this type of installation for that product. It sounds like the floor may have shrunk a tiny bit and it has pulled away. If this were severe shrinkage It could potentially start breaking either the tongue or bottom edge of the groove side. That hasn’t happened which is good. Find out from the manufacturer if they recommend this type of installation.

Filling grooves from shrinkage

Q: I have recently installed tongue and groove spruce floors. The boards shrunk a bit so there are grooves between most of the boards. I have applied a mixture of 1/2 stain 1/2 waterlox to the wood but am wondering what you would suggest to use as a final coating that would give a harder finish and also fill in the grooves? Thanks.

A: I have used Waterlox several times including staining a very large pine floor with stain mixed with the oil coating. It worked really well. Waterlox is meant to be a finish coat and there is no need to screen it between coats if you need to freshen it up. That is a big plus. However, it isn’t a hard surface coating. If you want that sort of finish I would use Poloplaz Primero. Great polyurethane and applies beautifully well with a roller. You will likely need two coats over the Waterlox but you will have to judge yourself after applying one coat. 500 Sq. feet per gallon.

It isn’t unusual the spruce shrunk and left gaps. I’d give it a full 4 seasons to see if some of them close up. There isn’t a fail safe wood filler I’ve used or heard of. If there is any movement between boards or even vibration, it will eventually crack and start falling out.

Gaps and creaking all over hardwood floors

Q: We purchased a brand new home in April 2010. Since then, every time we walk on the hardwood flooring, on the outer walls it makes cracking and creaking noises. Why is it doing this? It is very loud and what I would imagine a 100 year old home with hardwood flooring would sound like. Is there anyway to fix this?

A: I don’t know what this floor is installed on top of nor whether an appropriate amount of nails, cleats or staples was used. But clearly the floor is moving. It could also be expansion and contraction noises occurring. Do you notice any large gaps appearing or conversely do you see any cupping of the boards that would indicate expansion from moisture?

Follow-up Q: Hi! I took a picture of one of the boards [gapping] they are all like this on the exterior wails of the home. Our house is not even three years old yet. I’m jut wondering if it is normal or if I should be contacting the builder? Thanks for your help!

A: That looks like wide maple plank which is more sensitive to environmental changes in humidity than some other woods. This clearly is significant shrinkage. I’m wondering what the moisture content of both the maple and the structure it is fastened onto was at the time of installation. Yes, I think I would be calling the contractor. Tell him to bring a moisture meter with him.

Related Q: We had the floors redone on June ’09 after living in our house for about 8 years. We are starting to notice big gaps all over the floors to the point that dirt and/or dust get in these gaps. Is there anything I can do to fix these gaps or would I have to replace the whole floor?

A: It is likely that the relative humidity in the home is too low. Getting a humidifier working to bring the RH up to around 40% should help. A hygrometer is a handy little device to keep around the home too. I would hope by increasing the RH the gaps will close up to some degree. Tiny gaps are considered normal.

RH and moisture readings before installation

Q: I installed hardwood flooring on the main level and the top level of a new home as well as a hardwood staircase. The install was in Nov 2013. The floor on the main level is showing areas of gaping and splitting and so is the staircase. There is a lot of shrinkage in the trim and mouldings as well as some shrinkage in the kitchen cabinets and the solid wood cupboard doors in the same areas of the house.

The RH at the time of install was in the 40% range and the wood was in the house for at lest 72 hours before being installed.

The present moisture reading in the floor on the main level where all the problem is are 9 to 8 and up to 12 in some areas; the stair treads have different readings one is 7 and the next one is up to 13. When we take a reading in the basement of the floor and the sheeting for the first floor the meter does not give a reading because the level is too low for the meter to read. I have developed the basement and added a propane stove in the last year. The ceiling is a T-bar type with a drop in tile. Did this cause the staircase and the floor on the main level of the house to react in this way? The RH at present on the main is 38% and the basement is 30%.

A: It sounds to me the moisture reading of the wood products were not taken prior to installation. At any rate, significant heat rise coming from under the stairs and floors could significantly dry the areas you mention. You could add some moisture to the air, but 38% is not bad at all in winter, and I don’t think you would want to go much higher. It is possible none of the wood, stairs, floors, etc., were dry enough, or dry enough to be within range of 4% moisture content in the sub structure.