Is this true?

Semi Flex boxes last longer than regular wood foundations and are not prone to the creaks and groans that develop in the regular wood foundations. However when used with some heavier king mattress you could experience a ridge form down the middle where the two meet in the middle. There is no give in the seam which can cause this ridge when used with heavier king mattresses.

Are the last 2 sentences referring to 2 seperate pieces being used for the king size? Is that what they mean when they say where the 2 meet in the middle and there is no give in the seam? If so, would a coir mattress rug eliminate that? I was actually considering a semi flex. A local manufacturer sells and recommends them with their foam beds and even substitutes the semi flex with the Pure Talalay Bliss mattress because they say the semi flex is better than the foundation that comes with the Pure Talalay Bliss.

The site that I copied and pasted this from recommends heavy duty wood foundations for king size mattresses. I find the foundation to be a difficult choice because some of the wood slat ones having inconsistent quality and the better ones costing several hundred dollars plus shipping. Not into the DIY.

I just don’t like the idea of the wire or metal frames that some companies are selling and/or recommending for their mattresses when it will be used for a foam mattress. That being said,
maybe using a coir rug on one of these could eliminate my concerns although one mattress manufacturer that sells these did say that they can be a little noisy with a lot of movement.

Hi Napper,

Like many things, the devil is in the details, so it all depends upon the quality and style of semi-flex foundations being compared to the specific style of wood foundations. A good quality wood foundation with appropriate center support an 3" or less between slats will generally be quite a bit “sturdier” than a good quality semi-flex foundation. A wood foundation that is commonly used under an innerspring mattress with only 7-8 cross slats and a felt or cardboard deck on top of those slats would not be as strong generally as a good semi-flex foundation. Both styles of foundations can creak over time, as this is dependent upon use, type of frame used, humidity changes, use of a cardboard deck (in a wood foundation), and quality of assembly.

Yes, you are correct. This is in reference to two twin extra long foundations used for a king mattress. In a semi-flex unit, over time the modules can take a bit of a set in the middle area of the foundation, but along the edges, with the thicker gauge border rod and different support elements, it might not take the same “set”, resulting in a surface that will in effect be higher in the middle.

Just for clarification, Pure Talalay Bliss does not supply or manufacture foundations for their mattresses. There is a company called Ironwood that they recommend, who has the covering to match their mattresses, and they make a wood platform foundation that would work with a latex mattress.

Regarding foundation selection for their mattresses, from Pure Talalay Bliss:
Important Foundation Information: Pure Talalay Bliss mattresses are substantial in weight, and are designed to work on a solid, firm surface, not spring foundations or bases that are structurally not capable of supporting the weight of the pruchaser’s Pure Talalay Bliss mattress. Pure Talalay Bliss may require purchaser to provide proof of the quality of the foundation, adjustable base, or bed frame used in conjunction with the mattress if purchaser makes a claim under this Limited Warranty. Therefore, if purchaser uses inappropriate foundations, box springs, adjustable bases, or inferior frames with the mattress, such use will void this limited warranty without limitation. **An appropriate bed frame must completely support the foundation as well. Foundations must have an appropriate bed frame, that at a minimum meet criteria above.

While they do not explicitly describe the exact type of foundation to be used, I would have a concern with a semi-flex foundation under a heavy latex mattress over time and the potential for it to take a set and possibly cause sagging in the mattress and also potentially void any warranties.

The DIY wood foundations are usually quite simple to assembly, but if you’re not into that then I understand. Your other options would be to find a local retailer carrying a heavier-duty style of already-assembled foundation, or pursue another design. The DIY foundations will not be of a “finished” quality, as they are generally covered with some sort of a fabric coverlet.

[quote]I just don’t like the idea of the wire or metal frames that some companies are selling and/or recommending for their mattresses when it will be used for a foam mattress. That being said,
maybe using a coir rug on one of these could eliminate my concerns although one mattress manufacturer that sells these did say that they can be a little noisy with a lot of movement.[/quote]

Using a coir bed rug on top of a semi-flex can help minimize the “cheese slicer” effect of the wire network “pushing into” the foam base over time, but it won’t change the potential for the gradual sinking in that can occur in the semi-flex modules. A coir bed rug placed atop a finished semi-flex foundation with a non-skid covering should be quite quiet, as it doesn’t tend to move. If placed atop a metal platform bed with an exposed grid network, I could see the potential, at least initially for some sliding.

Phoenix

Would split foundations for a king mattress cause a similar situation where you would have to edges meeting in the middle? Would they cause a difference in the middle of the mattress? Would a 1 piece wood foundation be a better choice than splits?

You mention semi flex foundations taking a set in the middle, is there any similar effect with split wood foundations on a king mattress where the 2 edges meet in the middle? Any negative effect from using split wood foundations vs a single one?

When putting some of these wood slat foundations together, you start on each end and bring the slats toward the center and when you are done there are 2 slats side by side in the middle.

Hi Napper,

A good quality wood platform foundation using non-flexing slats tends to stay quite flat and firm and not bow. Using two twin extra long foundations versus a king sized platform bed base would result in a slightly shorter span for the slats (having extra perimeter wood in the twin extra long foundations), but with appropriate head to toe center reinforcement in the king sized platform base it can still provide very good support.

The design will of course vary with the manufacturer, but this would provide a little more support in the middle of the foundation, where most of the weight is typically concentrated.

Phoenix