Have you been staring at your rafters and thinking of the kind of post to support it?
Or are you trying to figure out which roofing support post will be ideal for holding your rafters and over your patio and deck? In this article, you will know all there is in a 4×4 post roof support.
A 4×4 post roof support is a post for an outdoor structure to support the rafters and complement the home’s architectural landscape and style.
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How Much Weight can 4×4 Roof Post Support?
When building a structure requiring a post or beam, you must adequately determine the weight the post will support.
A 4×4 roof post can support up to 4000 pounds when lying horizontally, while 4,300 pounds or even more when vertically.
If the weight of the post that will offer support is not known, you run the risk of further reconstruction.
There could be loss of lives and properties should the post give way due to the immense weight knowledge of the weight your post is to bear is paramount.
#1. Factors that Affect the Load-carrying Capacity of 4x4s
Some factors affect the load-bearing capacity of your post. Seen below are a few of the factors:
- Wood Species: The strength and densities of your 4×4 roof post are affected by the different species of wood. These species of 4x4s affect the amount of weight the post can bear. Since there are different species, each has its purpose. It is of note that denser woods support more weight when compared to a less dense wood. For a project requiring the post bearing substantial weight, it is ideal to go for a denser species like the Pine and Douglas fir.
- The Grade: The difference in strength and how much load your post can carry is evident with the correct grade of the 4x4s. You determine the grade by the number of splits, knots, and warping in the wood. You rank the grade from number one to four, with number one as the strongest and four as the one not recommended for anything structural.
- Load Type: When considering a 4×4 post, keep the load type in mind. There are two load types; the dead load and the live load. Dead loads are a load whose weight is constantly on the post, while live load changes daily. You consider these two load types when constructing your 4×4 roof post.
- Span: The distance a 4×4 post can travel is called a span. When considering their strength, you consider the spacing between the 4×4 posts. The shorter the span, the more weight it can hold, whereas the more extended the span, the less weight your post can hold.
- Length/Height: The length of the post is inversely proportional to the weight. The shorter the length of the 4×4 post, the more weight it can support, and vice versa.
- Moisture: Moisture in your 4×4 post can affect the weight-carrying capacity. Dry wood is more vital when compared to wood with moisture.
Can I use 4×4 Posts for Deck Roofs?
You cannot use 4×4 for a deck support post. Engineers built a deck support post in the past with 4×4 roof posts.
However, because it bows quickly, using 4×4 for the deck was stopped. The 4×4 post can’t withstand the enormous weight of the deck, causing the entire porch post roof to collapse.
A 6×6 post is better off when used for this purpose.
I recommend a 6×6 post for your deck roofing because it supports a great deal of weight and lasts longer.
The 6×6 post supports the heavier load, provides stability for an enormous deck, and has more room for notching.
How Much Weight can a 4×4 Wood Post Support Vertically?
When you use 4×4 wood posts vertically, about 6,000 PSI weight is supported. The amount of weight a 4×4 post supports depends on factors such as the wood grade and species.
You consider other factors such as; load parameters, types of footing, and support. All these factors significantly influence the weight a 4×4 post can support when vertically placed.
You use bracing when a long post offers additional strength and prevents bending. The shorter the length of the 4×4 post, the more weight it can bear.
However, the International Residential Building code uses a maximum of 6′-9″ height for a 4×4 post.
You consider the weight a 4×4 post can carry horizontally, factoring in safety and structure.
More so, the amount of weight a 4×4 post can withstand when used horizontally is 4000lbs.
Consider the wood species, grade, number of knots, and their locations, span, and condition also affect the load-bearing capacity.
When you are in doubt, I suggest you check with your local building department or a Structural Engineer.
Is a 4×4 Roof Post Stronger than a 2×6?
The load direction determines the strength between the 4×4 and the 2×6 roof post. A 4×4 post is stronger when the direction of the load is vertical.
A 2×6 roof post is stronger in the horizontal direction than its counterpart in the same direction.
However, the roof post’s thickness matters in the direction of the wood. The length of the 4×4 and 2×6 roof posts also plays a major role in their differences in strength and capacity.
The 2×6 post is more robust than the 4×4 roof post in one direction against bending. The strength in the case of bending depends on the moment of resistance; in turn, the moment of resistance depends on inertia.
But 4×4 roof posts have more compressive strength when compared to 2×6 roof posts. You use a section after you have a sound knowledge of loads and material.
Is a 4×4 Roof Posts Stronger than Two 2x4s?
A 4×4 roof post is stronger than two 2x4s. Also, when you use a 4×4 post vertically, it is stronger than a combined 2×4 roof post.
You treat both posts the same based on the difference stipulated by building codes when used horizontally.
The difference between these two roof posts is obvious. The 2×4 post is usually more common in construction than the 4×4 roof post.
To this effect, you can readily combine and use it in place of the 4×4 roof post. However, the tensile strength for both is virtually not the same.
Do you know: How To Cut 8×8 Post?
The table below depicts the striking differences between 4×4 roof posts and two 2×4 roof posts:
| 4X4 ROOF POST | TWO 2X4 ROOF POST |
|---|---|
| The 4×4 post is 3.5 inches wide by 3.5 inches deep. | The 2 2×4 post is 3.5 inches wide by 3 inches deep. |
| The 4×4 post can support 6,000 pounds vertically. | This post can support about 2000 pounds vertically. |
| This type of post is suitable for ground contact. | This type of post is not suitable for ground contact. |
| You use this post type with a Simpson post anchor. | This type of post does not use Simpson post anchor. |
| The cross-section of a 4×4 is about 4.95 inches. | The cross-section of a doubled 2×4 is 4.6 inches. |
| The 4×4 post is more susceptible to twisting. | The doubled 2×4 post is less susceptible to twisting. |
| This type is expensive and heavy | This type is cheaper and lighter. |
Conclusion
A 4×4 post roof support is a post for an outdoor structure to support the rafters and complement the home’s architectural landscape and style.
A 4×4 roof post can support up to 4000 pounds when lying horizontally, while you use 4,300 pounds or even more when it’s vertical.
The 4×4 post can’t withstand the enormous weight of the deck, causing the entire porch roof post to collapse. Hence, you can’t use a 4×4 post to construct a deck.
